<p>This came up as we are considering what colors to paint our house.</p>
<p>Dark colors absorb more of the sun’s energy, so cost more than light colors for electricity for air conditioning in summer. But for the same reason they cost less for natural gas costs for heating in winter.</p>
<p>Does anybody here know how this balances out, for a house in the Northeast/ mid-atlantic region? We’re near NYC, with four real seasons and humongously high utility costs.</p>
<p>I found one study on the 'net, a test house with light color walls cost $325 less in electricity for summer air conditioning that with dark color walls, but $54 more in gas costs during winter. But that was in San Antonio Texas, which presumably does not have the same winter weather we do, or the same utility costs.</p>
<p>I checked the Con Edison web site but could find no place that seemed like a place to ask them this question. (Lots of links to pay bills though…).</p>
<p>You can look up the number of heating degree days and cooling degree days on the NWS website for your climate. Heating and cooling degree days are indicators of how much you use the furance or air conditioner over a year.</p>
<p>If you are in a cooling climate (heating degree days < cooling degree days), it makes more sense to paint your house a light color. If you live in a heating climate (heating degree days > cooling degree days).</p>
<p>I don’t know that I agree painting a house has a significant difference on the interior temperature of the house, but if it does, it should have a similiar affect.</p>
<p>While dark colors absorb more, the total amount of additional energy they absorb is dependent on the material that is dark. Materials that have high heat capacity (like steel or water) will absorb more BTUs of energy than materials that have a low heat capacity (cedar siding). I think the difference of paint color for cedar siding would be fairly small.</p>
<p>Of course, your windows are the greatest source of heat addition and heat loss. Significantly more so than walls or ceilings.</p>
<p>Of course, the assumption is that your house receives the same amount of sunlight year around. It won’t, but that varies from house to house and no study will be able to predict your house.</p>
<p>I’d think most houses these days are so insulated that the color you paint the exterior wouldn’t have a huge effect. The color of your roof and quality of your windows would make a much bigger difference - at least it seems that way to me, a non-engineer.</p>
<p>Roofs actually radiate/absorb far less energy than walls because we can put as much insulation as we want in the roof. Walls are limited by the 2x4 or 2x6 thickness.</p>
<p>Windows are by far the worst offenders for heat loss/absorption.</p>
<p>More important than what goes on the walls is what is inside the walls. Heat loss due to poor insulation, and conversely, heat gain in summer is a big factor in energy costs. I used to know a lot of energy conservation professionals, and paint color did not seem to be an issue they talked about. Roof color, yes. Doors, windows, air leaks, big deal. I’d guess, and it is only a guess, that if your wall insulation is poor, this might make more of a difference than if the appropriate R level for your area.</p>
<p>Thinking of your original example, the other factor is sun angle in northern latitudes. Does it really matter to try to affect heat gain with dark paint when the sun is at a low angle? Minimizing the heat gain in the summer, when the sun is higher might be of greater significance. But depending on shade trees and roof overhang, might be a minor consideration.</p>
<p>All I know is Mayor Bloomberg is encouraging people with flat roofs to paint them white because it saves a lot on energy costs in NYC. <a href=“http://www.nytimes.com/2009/07/30/science/earth/30degrees.html[/url]”>http://www.nytimes.com/2009/07/30/science/earth/30degrees.html</a> While it’s true theoretically one can put lots of insulation in the attic, in most houses roofs are a big source of heat loss. Windows are bad too though not just because they have very little insulative value, but also because they are frequently poorly installed and may leak wherever there are moving parts.</p>
<p>Though it addresses roofs specifically and not walls, that Bloomberg article seems to address the general cost tendency, heating vs.cooling in NYC area.</p>
<p>"Scientists acknowledge that the extra heating costs may outweigh the air-conditioning savings in cities like Detroit or Minneapolis. </p>
<p>But for most types of construction, they say, light roofs yield significant net benefits as far north as New York or Chicago. Although those cities have cold winters, they are heat islands in the summer, with hundreds of thousands of square feet of roof surface absorbing energy. "</p>
<p>FWIW we have newly-insulated attic with light gray shingles, south facing house which gets lots of sun, no trees in front, stucco walls with some insulation who knows how much, replacement vinyl windows. All these features matter, but the only thing up for change any time soon is the paint.</p>
<p>monydad, what if the most energy efficient color turns out to be the ugliest, gloomiest color that your wife hates? Would you still paint your house that color? I’d be really depressed to look at my house every day and think how much I hated the color. There is no monetary value that can be easily attached to happy feelings, but I’m glad that every night when I pull into our driveway, I’m greeted by my cheerful, sky-blue craftsman house with snowy white trim. :)</p>
<p>"monydad, what if the most energy efficient color turns out to be the ugliest, gloomiest color that your wife hates? "</p>
<p>We have two schemes that both look good, one with the walls in a light color and another with a dark color.</p>
<p>If the most energy efficient color turned out to be the ugliest, gloomiest color that my wife hates, we wouldn’t use it. Actually she is the one who raised this question, she does not want to blithely **** away money for no good reason either.</p>
<p>Maybe if we find out the light one is more efficient we still might decide to go with the dark one. Or vica versa. But at least we might strive to make this decision informed of the economic consequences, to the extent they exist. Money does not grow on the trees on our street, at the moment.</p>
<p>If it seems likely to make $1,000 per year difference to go with one color scheme we like instead of another color scheme we like, I think that’s worth knowing, and considering. Given the findings of that Texas study, and the probable differences in utility costs between there and here, it seems worth looking into to me. YMMV. According to Payscale, the cost of utilities is 93% higher in NYC than in San Antonio, TX. Plus,that study was done a while ago probably.</p>
<p>But actually, pointlessly depleting the earth’s fossil fuel resources, for no good reason, is of some importance to me as well, money aside. We will probably never be in the house long enough to recoup the cost of the insulation work we had done this past year, but I thought it was just the right thing to do. Again, YMMV.</p>
<p>If you want to really save costs during the summer, get an attic fan for your roof. You would be amazed how it cools down the home. In my neighborhood, people thought I was insane to spend 400 bucks on installing one, but they quickly changed their minds when my AC bill in 90+ degree weather was 300, while their home at the same temp was 500+.</p>
<p>Attic fans also add life to the roof, so you will not have to replace it as quickly.</p>
<p>I also agree that I don’t think the color is a make or break difference in the utility bill, it is windows, insulation, ceiling fans, HVACs, etc. Even, things like older fridges and w/d’s will tally up the bill. In my home, we have plantation blinds in the home. During the winter I open them up during the day to heat the home, but close all of them at night to keep the heat from escaping. I reverse this process in the summer, by keeping them closed during the day, and open at night.</p>
<p>Even buying storm doors for your home will save you more money then the color of the paint.</p>
<p>I guess we should start an “energy efficiency tips” thread, someplace.
I agree attic fans and storm doors are good things, got them both.
Right now we’re just about to paint our house, is all.</p>
<p>I guess I mis-named the thread ambiguously, my fault.</p>
<p>I live in Texas and put a standing-seam metal roof with Kynar coating on my house. My electric bills peaked at $110 this summer - that’s for the hottest month - much less for other months. I can’t imagine paying $300-$500 to cool my house!!! :eek:</p>