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Will enclosing my porches during the winter help keep my house warmer? There is a lot of wind hitting the house, and I'm afraid that is causing a drop in temperature.

Tester101
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Anthony Powell
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    +1 to every answer that ignores R-value, and focuses on air infiltration. R-value computations are only valuable when it is the only factor (hermetically sealed). – Mazura Nov 07 '14 at 23:54
  • Looking at just the title, I thought it was a question from a game resembling a real life situation. I totally did not consider it could actually be a real life question. – o0'. Nov 08 '14 at 00:08

4 Answers4

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An enclosed porch can act as an oversized "storm window" for the part of the house it covers, so there is some insulation benefit. How much depends on how well the porch is air-sealed and insulated. It's probably a relatively small part of the surface of the house (unless it's a wrap-around porch), but it certainly won't hurt and, depending on prevailing winds and lighting conditions, might help.

An enclosed porch can also act as an "airlock", reducing how much warm air you lose each time you go in and out by preventing winds from blowing straight into the house. Again, probably not a huge effect, but it's there. And gives you a sheltered place to leave outdoor stuff like bicycles, or muddy shoes that you don't want to track into the house.

I doubt energy savings alone justify it. Those combined with increasing the year-round usefulness of the porch space might.

(Mine just has storm windows all the way around. It definitely does work as windbreak and airlock and so on. Its R-value for the rest of the house is probably negligible, but I still find it useful -- and it gives me a screened porch in the summer as well. Someday I'll upgrade it into a three-season space, but there's no rush right now.)

keshlam
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I have an 1930's vinatge house w a glassed in front porch on the east side. I open those windows in the summertime. Otherwise the porch heats up to 115°F or so, and that heat comes through the limited, 1930's style, insulation into the living room, where I have to pump it back out with an AC.

If I forget to close the porch windows in fall, winter makes the porch icy cold. That cools the wall to the living room, and I have to combat that with the furnace. Closing the porch windows will raise the temp out there by up to 25°F on a sunny winter day. It's not comfortable sitting out there, but it keeps the living room wall much warmer.

Wayfaring Stranger
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Unlikely. If your house is too cold in the winter, ans especially if it's very windy, you need to start by sealing off places where cold air is coming in. That will often help a ton. The next time it's very windy, just go around the house feeling for drafts and air currents.

After doing that, you can then start to improve your house's insulation. The attic floor is often low-hanging fruit since you can blow a bunch of cellulose onto the floor very inexpensively. If you have hollow walls, those can be blown full of cellulose as well (in the wall, it needs to be dense-packed) through holes cut in the top of the wall. Basement walls can also be a big win, but to do that properly, you need to add rigid foam insulation boards and make it airtight so moist air can't blow through the insulation boards touch the wall. After that, new windows or low-e storm windows can help.

iLikeDirt
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    Have to disagree with @iLikeDirt... I think that technically, no matter what, it would help keep the house warmer. The real question is, how much. It depends on a number of factors, many of which where IDed in this answer. Now, if the question were, is it worth it to enclose the porch, then the answer is probably no simply because, as was stated, there is likely a lot of other low-hanging fruit (i.e. cheaper, more effective options). – bobfandango Nov 07 '14 at 19:57
  • I don't see how enclosing an unconditioned porch could help keep the adjacent house warmer. If it's not heated or insulated, the porch is going to be the same temperature as the exterior 99% of the time, even if it's enclosed. The only way it could help is if there are significant air leakages from porch to house, but if so, it would make more sense to close those rather than the whole porch. – iLikeDirt Nov 07 '14 at 20:09
  • agreed for the most part, but you are ignoring air movement. If the wind is blowing, as stated in the question, then an enclosed porch serves as a buffer of relatively dead air. Convective losses would drop since the air next to the house isn't moving near as much without the wind. Imagine blocking part of a heat sink... Would the air blowing across that heat sink be as effective in removing heat? No. But as I said, this is a technicality. The question should have asked "is it worth it" and your answer is correct as to that. – bobfandango Nov 07 '14 at 20:12
  • While cellulose for walls and foam boards for basement are examples of ways of insulating those spaces, note they are not the only way. The full explanation of different ways to insulate is beyond the scope of this question (and asked already on this site) but I just wanted to point this out as this answer's wording implies there is only the one correct method. (I agree with answer in principle, just don't like the wording). – gregmac Nov 07 '14 at 20:48
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If your porch gets any sun, it should help. My dad enclosed his each fall and opened it back up in the spring to let the breeze through. Worked great, but this was in the high desert where it would be sunny and below freezing at the same time.

scollier
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