Thanks for clarifying your intent. We're self-employed and working upstairs all day. Duct dampers that can be installed at the boot in the ceiling could also work. And get the same effect (as a WHFan) , like my fathers house. David, Should I install soffit vents. Martin: Don't you mean it strongly pressurizes the attic? Whole House Ventilation First, we need to distinguish between three different types of ventilation fans. My attic is ridiculously hot if I install a fan (pull out hot air) to help cool my attic will my AC work better right now it takes two to three hours to drop the house 4 degrees. A few inches of re-used rigid insulation above the roof deck and batts of fluff between the rafters is less than half the cost of doing it with a combination of spray polyurethane &/or spray polyurethane + fiber blown in mesh. Whole-house fans are intended to be used in homes that are not air-conditioned. When the wind isn't blowing, the devices are no different from any other hole in the roof; and if the wind is blowing, the devices can potentially depressurize the attic, sucking indoor air into the attic through ceiling cracks. A. Thanks for sharing your anecdotes. The house has tons of windows, many louvered (so leaks/ventilation everywhere) and no attic insulation. There is a ridge vent, and one turtle vent. Q. Response to Jrowen42 It is noisy, but pretty powerful, and we try to remember to take advantage of the drop in temps at night. This popular and premium vent is a favorite among seasoned road trippers and fans of the open road for several reasons. In the U.S., this type of fan makes more sense in the arid West, rather than in the more humid Eastern part of the country. Remove the insulation from between the joists in the fan's location. Thanks for the help with the calculations Any Suggestions? One thing that comes to mind is fire damping since I will be creating a chimney. My contractor wants to use blown-in insulation. The house gets oven hot in the summer. Let's say it costs you $5 a month (or $35 a season) to operate. Find out if there's a standing pilot ignition running 24/365 if you're going this route. Sign up for a free trial and get instant access to this article as well as GBA’s complete library of premium articles and You might also need soffit vents if you don't have them, so that air can flow in there and then out at the ridge vent. That 20,000 kWh would go a long way toward operating a pair of thermostatically controlled, powered attic ventilators (operated off the same thermostat) that had fans both blowing air into and out of the attic, through gable vents, with a balanced pressure so that air was not sucked through the ceiling of the house. (Yes, we insulated and sealed the vent (drained the water and cleaned/painted them inside in the fall. A. Is your fan-coil unit in a hot attic? Is that correct? My experience has taught me to think beyond articles like this one. Several studies show that using a power attic ventilator does not always save more electric than it uses; even in a newer home with no cracks or air seepage. Another suggestion is to have a solar powered attic roof fan installed. Installing a fan won't help -- all the fan will do is bring more outdoor air into your attic. Attic fans are a bad idea in general, but especially if you have AC. The cost of a new roof for a modest size house is roughly $8000, or $500 per year for a roof that lasts 16 years. Response to Hannah Mills-Fee And, yes, unfortunately the AC equipment and ducts are in the attic. When the control predicts relatively mild weather, the ventilating blower will run at a lower speed than when hotter weather is predicted. Bathrooms are wet, smelly places that often are closed-in and unventilated. I'm not experienced enough with your climate to know whether a whole-house fan would work, but I suspect that it would work better than attic insulation. Another thing to remember is to cover the large attic exhaust vent in the off season. If I do it, I figure a few mornings and $200-300 since I can do it myself. But all of the soffit area is covered with solid ventless soffit. If your roof is uninsulated, the long-term solution is to install insulation with an adequate R-value in your roof assembly. Kris, As a result, the fans increase the homeowners' energy bills during the winter. My excursion into PAV's has yielded some important side benefits, not the least of which was discovery of this site. Interesting article. Talk about wasting energy! Verifying that the attic insulation is still there would be an important first step. It is raised up about 4 feet on stilts. Maybe you are talking about a roof-mounted fan that is solar powered -- a fan that is designed to pull air from your rafter bays. If there are signs that you have a damp basement, you'll need to address those issues. The key is solar reflectivity and thermal emittance of the roofing material. Of course the insulation is the better option if possible.). Anyway, I also have a house in Kauai but no AC. AC cycles on and off all the time with the t-stat at 76. If you believe that your house has a hot ceiling during the summer, the solution is not a powered attic ventilator. The heating svc company wanted to put one in but seemed like a lot of money. The most common kind of residential ventilation fan is one used to provide fresh air for building occupants. Dan, Also we have debated about putting in a whole house fan, since there are some weeks when its cool outside but hot inside the house with no wind outside to help. If this hot, humid air contacts your cold ducts, you'll get condensation -- just like you will on the exterior of a cold can of beer or soda that you remove from the refrigerator on a hot, humid day. Here is a link to some models that are not necessarily optimized for air sealing: Most whole-house fans require a rectangular opening that is at least 32" x 32", and often larger; some whole-house fans are 48 in. The potential for hazardous conditions is elevated in homes utilizing power exhaust fans during the summer when gas appliances are on at the same time the fan is on. Its casing is made of aluminum, and the solar panel is made of polycrystalline. How often should I run it? Amtrak Solar confirms this by bringing on board one of the most powerful models of attic solar fans that needs no drilling on the roof to fit it in. This increase in your electric bill is especially guaranteed in homes without AC (because there is no possibility that running the fan might decrease electricity devoted to AC). Should we turn it on when it's hot out? It is made in the USA in San Francisco, California. Most powered attic ventilators are controlled by a thermostat so that they turn on when the attic gets hot. TheDoc46 said: yes attic is vented thru vents in the soffits. Attic fan reduced my electricity bill The plans called for R38 in all ceilings, R19 in walls and crawlspace. If a house has been air sealed by someone with an understanding of the air leakage, then it would seem that the depressurization would be minimal and the attic fan could then be beneficial. The answer depends on the insulation details (and the airtightness details) of your ceiling assembly. A better option would be the TC1000-H fan from Tamarack -- a model with an automatic insulated damper that prevents heat flow and air flow when the unit is not in use. Ideally, your fixtures should have both features: box enclosures to keep attic insulation slightly away from the fixture and recessed lights with built-in thermal sensors. For more information on this issue, see All About Attic Venting. In those circumstances, insulation doesn't help. Alas, air doesn't pay any attention to the smart arrows in illustrations. There are soffit vents but no ridge vents. Thank you for this informative, well-written article. ", Q. In the summers the vents spun day and night relentlessly. I imagine this hole would need to patched. You either want one or you don't. If air leakage is minimized, and depressurization is controlled with either a balanced fan or adequate openings for incoming air then it seems reasonable that the amount of depressurization would minimal and the attic fan could be beneficial. Q. I've looked at other houses in the area. "Our simulations and measurements have shown that asphalt shingles applied over vented roofs in hot-dry climates operate warmer than the same asphalt shingles applied over unvented roofs in hot-humid climates. A Tjernlund 6" fan is rated at about 530 cfm and draws 125 watts, an 8" pushes 670 cfm and draws 210 watts so I am not too concerned about electrical operating costs it if increases the comfort of the house and reduces the a/c load. How important is insulating the fan cover? So, will installing additional venting to attic solve the icicle problem? Any advice is much appreciated! This happens were the two levels of the house meet. I spent some time researching the Tamarack HV1000 after the author's recommendation. So I guess there would have to be a duct from the fan discharge through the roof. I've been an energy engineer for over twenty years. Today was low 80's and a thermometer inserted one of the ducts registered 95. To determine whether your argument has any merit, we need to look at each of these three assertions in turn. Moisture, though, is the real problem since it can create potentially hazardous mold and mildew, eating away at your walls, ceiling, and trim. It seems like a big tradeoff between winter efficiency and summer comfort. In some of the areas, I … Thanks, Response to Rusty Tools (Comment #106) The evenings and mornings here can cool down to the 50's even if the days are in the 90's, which is one of reasons grapes grow so well here. There are two sections that are showing condensation and this dripping water. If you are talking about the lack of ceiling insulation, you're right. The small window unit is plenty to keep the house comfortably cool. My 7 Pros Cons Of Attic Vent Fans Yes Or No Home. Combining an attic power vent fan with a ridge vent is usually not recommended because: It could reverse the natural flow of hot air out the ridge vent. I'm constantly up against folks who sell or have bought powered attic ventilators for use in Florida. A. Whole-house fans are sometimes confused with ventilation fans that provide fresh air. Yes, Ridge vent is an excellent option that allows hot air to escape efficiently from an overheated attic leading you to energy savings in the fact that your cooling system does not have to work as hard during those hot summer months. Your article comes across as biased. While the correlation between shingle temperature and longevity has not yet been definitively shown, it remains true that anyone concerned about elevated shingle temperatures should simply choose white shingles. There’s a lot of confusion surrounding attic fans. Complaints about the noise level, inadequate airflow, cheap plastic components, malfunctioning remote controls, etc. Thank you Martin. Regarding the heat source, no question it is the ceiling. Like so many other "plug in" Can an attic fan offer some benefit? For venting there is 1 gable vent, 1 turtle vent, and 1 non working power attic vent, this is on the upper level (bedroom section). If the attic fan keeps the house cool enough so that the owners leave the AC off, there is almost certainly an energy benefit. According to David Springer, the president of Davis Energy Group, one of the main consulting groups that developed the NightBreeze, ‘It is possible to achieve 6 percent duct leakage in a system that includes the damper.’ The wall-mounted NightBreeze control replaces a conventional thermostat. This conclusion isn't speculation; it's based on pressure measurements. Even running without water is good to act as a 'whole house fan' at night. I would be very happy to assist you in a thorough market overview which I do regularly for the http://www.WholeHouseFanGuy.com. Present day. I called an air conditioner repair man. David, 3. Most of these fans require an 8-10" duct. When I called the attic fan company I'd intended to get 1 whole-house fan installed, however when the installer came out we realized that the upstairs of my home had a separate roof that wasn't connected to the lower level roof, so he said I would need an attic ventilator on the lower roof. Community Rules apply to all content you upload or otherwise submit to this site. Just for fun, here's a photo I took at a 2004 built Minneapolis townhouse - yes, this attic was completely uninsulated. depressurization was enough to increase cooling costs. I have plenty of soffit, ridge and gable venting to allow the air to escape under the pressure. Do you have soffit vents in play at your house? I have very little insulation in my attic. All this and trying to massively conserve water and reuse water where possible. Is it a crawl space? Now all I have to do is satisfy the WAF, the Wife Acceptance Factor. Response to Kris Knutson Thanks for the response, i am We still believe this is a good idea. Click here to see a website with many inexpensive models of whole-house exhaust fans for flat roofs. Consider a less-expensive solution that may have some drawbacks. But the house is incredibly comfortable. In what year were those studies written? Recessed light fixtures are commonly designated as "IC" (insulation contact) or "no IC" (no insulation contact) to indicate if they can safely be installed with insulation directly touching the canister. Do you have actual references? In the Coastal plains and East Texas the humidity make the whole house fans not a reasonable solution. ... As long as shingle manufacturers ignore the effects of shingle color as a determinant of temperature, they may be admonished for asserting so strongly the importance of venting to control temperature. Response to Green Asalep Thanks for your help, my wife thinks I am creating a problem where none exists. To perform the calculation you requested, we'll have to make some assumptions. If you want a cooler attic, you need to install insulation along the roof slope. The fan pulls warm air from the interior of your home and blows it into the attic. Dana: Yes, that's right. Is an attic fan a good investment for my home? Engineering question: How much pressure is developed in a hot attic? It sounds like you have galvanized ductwork. The same can be said for any mechanical equipment in the house that is not operating correctly. Georgia Pulls the Attic-Ventilator Plug (Sort of), Home Energy: Finding the Whole-House Fan That Fits, California Energy Commission: Whole-House Fans, Iowa State University: Whole-House Fans for Summer Cooling, Home Energy: Drawbacks Of Powered Attic Ventilators, FSEC: Performance Assessment of Photovoltaic Attic Ventilator Fans. Related . A powered attic ventilator (attic fan) has a different purpose: it is designed to lower the temperature of an attic by exhausting hot air from the attic and replacing attic air with outdoor air through roof vents. The insulation on the duct is in very bad shape. A blower-door test will tell you more about your air barrier details, and a few small inspection holes will tell you more about your insulation details. This prevents hot air from seeping into your home and driving up the temperature in … Even if I run the AC for several days in a row. Also note that when the AC is on, stack effect causes a house to pull air from the attic. Thanks for the article. Response to Cathy Shin attic wit… Do attic fans helps improve attic ventilation even if the attic already has ridge and other vents? Attic Fans Again ‘The upstairs thermostat is set to 80°, so it’ll start ventilating when the outdoor temperature drops to 75°. I know there will also be the potential of the attic air pushing its way into the house through cracks as well. You may wind up with a cooler upstairs, but it will be a really inefficient way of achieving it. This provides much-needed ventilation, and is a powerful addition to your Whether the investment in the equipment can be justified is another question.’ ...". Great post still! Even adding the necessary cosmetic and structural elements, it would be reasonable to build this 1" plus thickness into a flat insulating cover mounted below the fan opening, on the ceiling, inside the living space. More than 50% of the attic fans I see do not work and have current still live to the motor. Chris, Get free shipping on qualified No Free Ship To Store Yes Attic Fans or Buy Online Pick Up in Store today in the Building Materials department. Become a GBA Prime member and get full access to GBA articles, enyclopedia, videos, CAD library, and more. Installing an attic fan costs, on average, $300 to $600 with the average homeowner spending around $500 on installing a gable mounted1 electric vent in a 1,000 sq.ft. The interactions of the stack effect, wind, HVAC equipment with duct leaks, and attic fans are complicated and unpredictable. If you need attic fan parts we have them at everyday low prices. "Do you think there's a way I could extend the wiring & install an indoor manual controller on the two ventilators & open the access hatch into the attic fully & just turn the ventilators on once it has cooled off outside?". Your comments about Tamarack are surprising. This might mean installing rigid foam insulation above your roof sheathing the next time you need new roofing. There are many reasons to doubt that your proposed fan installation will change the temperature of the attic enough to save any of the energy required to operate your air conditioner. In addition to providing nighttime ventilation cooling, the NightBreeze system provides year-‘round whole-house ventilation. If I decide to continue, I will inform you of the results, it should be fairly simple project. And I accept your assertion that you have no financial interest in promoting powered attic ventilators. I created 2 additions and extensively remodeled our now 1,800 square foot single story rancher in 2010 and 2007. Most ceilings are leaky. Make sure that there are sheet-metal screws in each duct seam. There was at one time a whole house fan but at some point it was replaced with an air handler in the attic with hard duct. Does the whole house fan allow for adequate air circulation even in the winter to prohibit mold growth? Still, an example calculation for an average home in New Jersey, and another in Vermont, would be enlightening. Before providing a simple yes or no answer to this question, you must understand that there are a couple of types of attic fans available on the market. But as long as you're making a cover, why not use at least 2-inch-thick rigid foam instead of 1-inch-thick foam? If you live in a hot-dry climate with cool nighttime temperatures, whole-house fans are a good choice for energy savings and comfort. Definitely insulate the roof and add a radiant barrier. Currently I have the access panels to the 2 attics opened a few inches, hoping this will help draw hot air from my house into the attic so it can be ventilated. So they worked great. There's also still the problem of using all that power for something that's not necessary. Blowing in additional insulation is not an option at the moment financially. "Should I install soffit vents, or just add more turtle roof vents?". I have emailed the manufacturer of the home asking for any information they can give me. As a curious professional, I was willing to risk the investment to see for myself what effects are. A whole-house fan designed to lower indoor temperatures at night when the air conditioner is off. Yes. The attic ventilator was much cheaper, so I opted to get two of these installed & see what happened. It's inoperable (no power even connected to it) Thanks you in advance for your comments. If you see mold in an attic (and you know that you don't have a roof leak), it's almost always a sign of a leaky ceiling. Sad that we have to go to these lengths after building with black roofs. Other factors have not changed. I'll repeat Bill Rose's words: "Ventilation is like a little boy who goes around the house looking for a job. An investment in ventilation cooling equipment makes more sense in a dry Western climate than in a humid Eastern climate. There certainly shouldn't be enough heat flow downwards through the R-38 ceiling to cause any problems in your garage -- certainly not enough to merit the installation of a powered attic ventilator. 1 by builders and are the highest attribute made in the USA! With the screened vent opposite the fan, it seems I wouldn't get all that much draw from the interior of the house, and if I did, it would be cool outside air anyway. Radiator FAN." Response to Carlos Gonzalez I've done this a couple of times due to recabling not being a practical option, but with a clear warning that replacing the switch will be a regular event. Asphalt shingle roofs last 30 or more years in Vermont, and only 15 to 18 years in Texas. Radiator FAN." Regardless of the insulation level there is always a benefit (in the summer) to a cooler attic. Outdoor dew points reach the 70s F in MI in the summer, making it uncomfortable indoors even at less-than-torrid indoor temperatures. From start to finish, powered attic ventilators are nothing but trouble. My home is in the Sacramento CA area. This approach usually increases rather than decreases your energy bills. The most common mistake homeowners make when installing insulation is to block the flow of air at the eaves. Another Silent Hill inspired horror game is Silent Insanity P.T, created by a fan of the original P.T teaser game. While a small window AC unit that runs a high duty cycle will fix most humidity issues, a single right-sized mini-split that runs nearly continuously (but at lower power than window units, operated in "dry" or "dehumidify" mode if not keeping up with the humidity in normal cooling mode) would provide more comfort, and more quietly to boot. It seems like the primary argument against using an attic fan is that it could cause a pressure difference, and cause cooler air to be sucked into the attic from the living space. "How do the old fans compare to the new ones in efficiency?". Other Solutions To conclude from that point that ALL attic ventilation is ALLWAYS a bad thing surely can't be correct. login. Q. Yes or no to whole-house fans? Roofers hate them because they are a frequent source of roof leaks. Increase your ventilation area, or consider a different solution. Let's assume that the attic temperature is 32°F, and the indoor temperature is 72°F. Here is an explanation of the physics: In the summer, your ducts are cold (because they are conveying cold air from your air conditioning system to your registers). And what's what the "tight ceiling" claim over and over again? Between your comments and Martin's, it sounds like this isn't really the best idea for my setup. Jon, Scott, He said there was condensation on the trunk duct. Your roof assembly has no insulation; that means that the rafter bays are empty. I use the bituminous foam (red stuff) for everything. I'm not sure what you mean by "a heat loss nightmare in winter." In theory, if your ceiling is perfectly airtight, you could limit or eliminate depressurization problems. ", Insulated Rooflines and Shingle Temperatures: Take a look at all those cooling fins. Thanks for the response, i am still interested in cooling the attic and I might try it after monitoring attic temperatures before and after to see if it makes much of a difference. I never had a problem with icicles before the new roof and gutters. Q. If the air handler is located in the attic, the air intake grille can be mounted in a gable, in a doghouse dormer, or at the top of a false chimney. That will reduce the transfer of heat from your hot roofing to the interior of your home. Response to Gary Seifer I can change this set-point, however I'd like to avoid having the ventilator run constantly. Do I need a bigger fan? That makes Other than making sure all second floor ceiling insulation is air tight and there are adequate soffit and ridge vents in place, is there anything else I can do? I think I will still need it at times to reduce garage temperatures regardless of insulation and passive ventilation improvements. Essentially, it is a climate where the outside temps are always comfortable but the house does build up heat during the day and needs some cooling. General Discussion - Solar attic fan Yes or No? For more information on the purposes of attic venting and cathedral ceiling venting, see All About Attic Venting. Bought a house with a whole house fan This means it can only cool 1-2 rooms, not a whole house. I picked one inch of foam in my example to match the R-5 mentioned in your article. My article provides several links to studies by researchers, including researchers at the Florida Solar Energy Center (FSEC) and Advanced Energy in Raleigh, North Carolina. I have a metal roof, I am getting icicles on my gutters. In North TX and OK (where wife grew up, and West Texas attic fans were great. My own experience points to anecdotes showing the attic fan is beneficial. K., Evan, Response to Jon R Cooler asphalt shingles last longer than warmer asphalt shingles. Hannah, Most experts don't see any advantages to turbine vents (or whirligig vents). Do not place smoke alarms closer than 3 feet from any furnace or A/C supply and return grills or registers. I wonder what the energy consumption difference would be, between an R-5 cover, and the R-26 advocated as the low end by Erik North. Lee, Whole-house fans installed in attics may also require extra roof venting. Moreover, if you use a powerful fan for your proposed pressurization, the fan will quickly remove all of the cool air from the crawl space, and the fan will be pressurizing the attic with hot air drawn from unknown sources, but probably from outdoors. The total area is 37.7 square feet. Penny, SCOTT: No, I’ve checked most of that. Smells are merely an annoyance. So everything else being equal, any house would benefit from a cooler attic.". I have never used one, but it seems like a good system. First things first. Will they cool the home? If the air infiltration is minimal, it would seem that a 90 to 100 degree attic would be easier on the the AC than 130 degrees. You are correct, of course, when you note that insulation doesn't stop heat flow; it merely slows it. No Soffit vents Q = A • U • ΔT = 37.7 • 0.038 • 40 = 58 Btu/h. Thanks again! Also, a local home center suggests closing off the other gables and forcing the air to recirculate through the soffit vents. I was thinking about adding some sort of powered attic ventilator. ‘I was convinced it would never work in Florida, but Danny Parker [from the Florida Solar Energy Center] convinced me otherwise,’ said Springer. http://www.atrendyhome.com/romowhhofano.html, Here is a link to a Tamarack fan that is optimized for air sealing (and that provides high-R shutters controlled by a motorized operator): Thanks You can't cool a space under those circumstances without an air conditioner. Who cares what your attic temperature is? Attic ventilation fans help cool air your attic by pushing out the stifling hot air from inside the attic and bringing in cool air from outside. Again, I am most concerned by the ducts in attic space warming up and transferring heat to interior. I guess it would have to be pretty big, too. David, I am considering, if such a product is available, installing motorized registers on each duct where it enters the room so they are normally closed, but open when the air conditioning system starts. User #98347 8382 posts. And the Attic power vent fan pulling all the heat up and out of the house. If I don't depressurize the attic and I don't have leaks, what is the downside? A ridge vent is basically a hole in your roof. Ridge Vent vs. Attic Fan? This can mean that there is a range of different costs associated with this project. The house we owned in Fairfax VA had an existing attic fan & gable end vents when we bought the place. Does not have any soffit vents. "Is it worth replacing a functioning fan?". It is interesting that asphalt single warranties are based on having attic ventilation to code or the warranty is voided. The physics say that a lower attic temperature (at the same dew point) will cause even more duct condensation. So does ventilation to the outdoors when outside is cooler than inside and purely internal air movement when it's not. Yes -- especially if you buy one of the Tamarack models. Attic Ventilation Fan I was thinking of installing one in my house, but our furnace is in the attic. "Will the old covered up soffit vents continue to work?". Martin. Don't listen to anyone that Move the R38 batts to the garage attic. How Does an Attic Fan Work? (assuming even a rudimentary level of air sealing). Why should whole-house fans not be installed in homes with a furnace in the attic? Strip off all of the deteriorated insulation and throw it away. For more information, see this article: "My House is Too Hot.". It's sad, but it's true. The Tamarack Technologies HV1600 whole house fan requires no maintenance and has an R-50 insulated doors, which, when not in use, form an airtight seal between your attic and living space. The beneficial effects of solar-powered attic fans, if any, are limited to a subset of houses -- those with airtight ceilings. Ceiling is sealed, and it is made of gypsum. So everything else being equal, any house would benefit from a cooler attic. As a general rule unless a homeowner has a highly qualified person to evaluate their house, I think its safe to say that attic fans should be avoided. Utilizing this type of fan in our area will introduce potentially humid and unfiltered exterior air into your home. My husband and I are closing on our first house next week (we live outside Chicago), and one of the red flags in our home inspection was the non-working attic fan. The house had a removable cover to get into the attic. After all, the cellulose insulation doesn't require any electricity. And then the main part of my roof/attic has NO ridge vent but does have gable vents on both ends. The discussion was centered around powered fans and vents. Just because insulation slows down heat transfer rather than stopping it, doesn't mean that insulation isn't the best (and most cost-effective) way to prevent hot attics from making homeowners uncomfortable. Where? An attic fan is what it sounds like—it’s a fan installed on the ceiling of your attic. "One study showed that shingle life is reduced by less than a year on homes in Miami with no attic ventilation.". who cares how hot the attic is? In your next case -- a hypothetical house without any AC -- does an attic fan make sense? A whole-house fan is a good thing, as my article explains. Let me know if I have misunderstood or miscalculated. With a semi catherial ceiling on the middle floor ( house is about 1900sf). If you have installed enough insulation on your attic floor, a hot attic won't make your house hot. Choosing a whole house fan attic ventilation fans pros and cons image balcony broan 1600 cfm power gable mount attic ventilator 12 best rv vent fans and covers reviewed rated in 2019 roofs effective whole roof system using ventilation. Martin, Gary, I'm curious how this would be the case, as there are vented soffits completely around the perimeter of the house. However, if you really care about shingle temperatures, the best solution is clear: choose white shingles! Tyler, If you do have ductwork or HVAC equipment in your attic, make sure you seal any leaking ductwork and make sure your ductwork is wrapped with insulation. Attic fans are a necessary part of every home. "Am I understanding correctly that if the attic area is conditioned and unventilated that I need to introduce some method of whole home ventilation?" I'll get some temp readings, from the attic space and garage. We put two in our attic, one of those solar roof vent fans, one a gable fan, and it does wonders for the attic temperature. It's cheap and it doesn't require any electricity to run. I'll have to check to see what kind it is. Look in your basement or mechanical room for an HRV or an ERV. There is a lot of confusion surrounding attic fans. Several manufacturers make whole-house fans for homes without attics. I looked on Amazon and some other review sites and there are a lot of negative reviews of the HV1000. When HVAC equipment is in the attic Of course if the attic fan isn't working correctly and is running all year long that would be a significant problem. Don't listen to anyone that tells you new attics don't need to be inspected, or that attic access panels shouldn't be opened. It's possible that I misunderstood, and the "gable solar fan" will not really be installed in the gable. There was one large flaw with the fan though, while the large fan duct was insulated and it had a damper on the end that exhausted to the attic, the heat build up in the attic caused heat to flow back into the house and would noticeably warm the house during the day. A. A room dehumidifier doesn't really help either- it just turns the latent heat of vaporization of the water it is removing into sensible heat (= higher temperature air). I took another look. We live in NC, it has rained every day for a month when this happened while being in the 90s. If it doesn't -- fix the panel. As it happens, there is a 6 sq foot cutout in the OSB boundary between my garage and house attic so the garage exhaust drew a bit of the hot air via intermittent soffit vents. I am curious if the author has personally installed or used the Tamarack products, and if he has an affiliate relationship with that company? Find out which is best. I thought I had made a large mistake, but I mostly fixed that problem by wrapping the duct with more insulation and by modifying the damping system creating new damper flaps insulated with foam sheet. The standard solution -- and any HVAC contractor in North Carolina should know this -- is to make sure that any attic ducts have sealed seams (this is usually accomplished with mastic or high-quality tape) and that the ducts have adequate duct insulation. However, the cost was prohibitive, so I installed an attic fan. I recently bought an electric attic ventilation fan in order to cool my attic space. Well, to me two anecdotes are NEVER COVER ATTIC SOFFIT VENTS WITH INSULATION use rafter vents and soffit vents to maintain airflow. 2. It is not a matter of comfort, but rather, a matter of survival. On my home this meant cutting inlet vents in the wall or garage door. Since I've already wasted $1050 for the two attic ventilators, do you think there's a way I could extend the wiring & install an indoor manual controller on the two ventilators & open the access hatch into the attic fully & just turn the ventilators on once it has cooled off outside? But the outdoor air is the source of the moisture -- so that proposed solution is clearly counterproductive. Since whole-house fans are relatively powerful, they quickly exhaust the hot indoor air, allowing cooler outdoor air to enter through open windows. Yet (if I understand correctly) you have R-38 insulation on your garage ceiling. To answer your questions: (a) No, I have never installed a Tamarack fan, and (b) I have no affiliation or financial relationship with the manufacturer (and neither does GBA). No other factor, including attic ventilation, plays as much of a role as do color and orientation. But it's too bad that you don't have a louvered opening in your ceiling instead of a hatch that needs to be opened and closed. Your article does a great job of outlining how this happens. Whats wrong with a large CFM attic power vent fan (say 1400-1600 CFM) and a set of ceiling shutters ? My understanding is that it is possible that my attic is too hot (I have adequate insulation since I added some prior to new roof and new gutter install. The consideration is that a powered attic ventilator will alleviate some of the heat load on the top floor of your home, whereby providing an energy savings from reduced use of your air conditioning system. By 5:00, it's rarely above 70F outside, even if the house is hot. Attic ventilation does not deserve the attention it has received in relation to shingle durability.” If your clients prefer cool shingles to warm shingles, the amount of ventilation behind the sheathing is far less important than the shingles’ color; so advise them to choose white shingles. The advent of smart and automated homes are increasing the availability of these products, I just need to find the right system and products, I only need 6 of these smart registers or duct dampers. Using the Sun to make the electricity for this fan, however, makes it only marginally better than its grid-powered cousin. But having the ducts & air handler in the hot attic means as a system the AC is running at very low "as-used" efficiency. Living the the San Fernando Valley in the summer we would often run the AC for a few hours during the later part of the afternoon and then switch to the whole house fan once the temp outside fell below the AC set point. Response to Mike Baldinelli We live in south east Texas. There is a basic fallacy to all attempts to move more air through an attic, since moving lots of air through your attic isn't the best way to keep your house cool. It sounds like you wanted to install a whole-house fan, but ended up with two powered attic ventilators instead. The question is if the house, including the attic, is very well insulated is there a application for an attic fan. That said, if we examine the heat flow across your hypothetical R-100 attic insulation, we will find that the heat flow is so small that any heat flow -- even if the attic is at 160 degrees F -- into the conditioned space below will be so low that it doesn't represent much of an energy penalty. I can't find a definitive answer as to whether or not powered attic fans are a good idea if you don't have AC or a whole house fan. Night Breeze doesn't need windows opened Thanks, Martin. Response to J Wing Whether it makes sense to install insulation depends on your budget, and how long you intend to live there. But let me finish explaining the difference I am contemplating in insulation location. I priced getting open foam insulation at the roof line, but that solution is price prohibitive to me at the moment. Garage batts look thinner, perhaps R19 and not as well placed. Most attics are vented; for years, this was required by code. Trying to create increased energy and water efficiency at the margin. Garage? (we hope the amount of air being exhausted through the attic floor is minimal because the house is air sealed). Your plan to install an interior cover should work fine. hi, thanks. Just use the whole-house fan when nighttime temperatures are cool and daytime temperatures are hot -- that's all you need. There are code complaint exhaust fans available w/dampers but displacement of the air has to be addressed, especially since I have a gas WH in the garage, as most CA homes do. The short answer is no, not significantly. I'm sure you will tell me it's a bad idea. The problem is that in most cases, there is no one available to accurately make that determination. The problem is not the hot attic but the ducts in the attic. Q. Before providing a simple yes or no answer to this question, you must understand that there are a couple of types of attic fans available on the market. That statement is only true during the summer. BTW, I live west of Philadelphia, PA. Response to Dan Puccio This article strongly recommends against the attic fan, but the only solutions presented to problems such as mine are very expensive. There are two devices commonly called “attic” fans: the whole house fan and the attic venting fan. if late in the afternoon the house temps rise above the outdoor air temps there is actually a cooling benefit. JetFanUSA.com Response to Rusty Tools (Comment #107) He can do some things well, but can’t do anything really well.". This assumes that there is a cooling system in place and operating. In fact, energy raters and home performance contractors who do blower-door testing know that it is very rare to find a house with a tight ceiling. With all the home automation occurring, a plethora of products are beginning to emerge, but so far what I have found are registers controlled in individual rooms by temperature and humidity. Since humidity is uncontrolled when the AC isn't running a significant duty cycle it stays uncomfortable even at lower temperatures. "Am I correct in noting that a properly 'conditioned attic' would have zero vents in the roof? If the time ever comes when you can afford to fix your home's problems, you need to convert your vented unconditioned attic into an unvented conditioned attic. If you have any east-facing or west-facing windows that get direct sunshine, you should check whether these windows have low-solar-gain glazing -- that is, glazing with a low SHGC. A properly maintained home doesn't have cracks in the ceiling.". Here's one for you. His recommendation was to get an attic ventalation fan and that should take care of the problem and we wouldn't need to replace anything if we did that. Response to Kay Alldone Response to Tyler Davis Expand Signature Lopi Liberty in the … Running a fan always requires electricity. While I am planning on insulating the attic properly, is there sense in me having an attic fan as well? Conditioning the attic or rerouting the duct work is completely impractical or way too costly in this instance. You are basing your hopes on the "smart arrow" theory -- namely, that the air entering your attic will follow the "smart arrows" shown in diagrams produced by soffit vent manufacturers. A ceiling grille measuring 32"x32" or 36"x36" isn't unusual. A. Take your pick. Again, keeping other things equal to your example, this would give us a seasonal cost difference of roughly $6. In addition the the article that Charlie suggested, you may want to read this one: Prevent Ice Dams With Air Sealing and Insulation. Just as a note : We usually only run the AC when it is so hot that we just have to (which is not often). The Tamarack fans move fewer cfm but use less energy and seal tightly. While this type of work-around may help, it would be better to solve all of the design problems. Whole House Fan Installation The first step would probably consist of installing some attic insulation. How about the un-powered vents? I assume that your garage is not conditioned. 2. Once the outdoor temperature is equal to or lower than the indoor air temp, air leakage in the attic floor isn't hurting anything at that moment.). My 7 Pros Cons Of Attic Vent Fans Yes Or No Home Inspector. Increasing duct insulation is part of the plan, I have already wrapped about half of the duct work, which means I have done the easily accessible part. Is that correct? Either approach can cause unexpected side effects -- in the case of your proposal to pressurize the attic, you might end up forcing attic air (or crawl space air) into the home through ceiling cracks. And they are; I can't argue otherwise. Thanks. Since installing the PAV no heat to touch and the garage is more comfortable. There are also 12 ground level windows (in 3 dormers) in about 500 square feet of space. If it's getting it's combustion air from the attic it can still backdraft, but the flues are usually plastic, and pretty clean. In the summer, you can drastically reduce the temperature in the attic, helping to lengthen the life of the roofing shingles and sheathing. Ergo, buy a high efficiency (40 watts, 15 cents a day) gable mounted PAV to reduce the radiant broiler effect on the ceiling of my garage. Tamarack fan recommendation You propose the question "who cares how hot the attic is if there is enough insulation in the attic floor?"