[Sandsam]

For a house of the same square footage - let's say 3300 sq ft - is the cost of A/C significantly higher for a two story vs a one story home?


As I think about my move to Naples, I'm wondering if it makes sense to spend more on a one story home rather than the less expensive two story because of the cooling costs. I've heard stories of $1000 monthly electric bills. I'm not sure that's true, however. I know most two stories have two A/C units. Does that make cooling significantly more?


Any thoughts? Thank you.

[BNBR]

My one story home as 3 AC units. On a 3300 square foot home, it will probably have 2 units. I wouldn't think 2 story v. 1 story makes a huge difference. Even my office with 4 AC units and equipment running all day, in a horribly insulated building sees and electric bill around $700 - $800. I wouldn't imagine you ever seeing a $1,000 electric bill unless you are growing drugs in a shed.

[markjames68]

For a 3300 square foot home you will likely have two units - a 4 ton and a 3 ton (give or take). Your electric bill in Naples, assuming you're on FPL which you should be, would likely be around $200-$300 a month if your AC units are efficient.

I have a considerable amount of plugged-in gizmos, computers, etc. and I'm probably only averaging a bit more than $300 a month during the peak of summer. About the same during the winter with the pool heater running.

A one-story home will likely have higher ceilings (my great room is 15') so you still have all of that cubic feet to cool. I'd recommend having efficient ceiling fans in the main rooms.

Now, if you have a leaky home, old AC units and are with Duke Energy I could potentially see $1000 a month in the worst, worst case. But that's still really high.

[stumble]

3100 SF ranch with pool, Highest electric bill this summer was $150 FPL. Lots of large live Oaks shading south and west side of home. 2 AC units. (Day & Night)

[aridon]

There isn't a significant difference ASSUMING that the homes are equally insulated. In fact, I'd argue the two story home would have an advantage with all the extra space over the dwelling acting as insulation for the floor you're actually using.

Obviously you need 2 zones, one for upstairs you can leave at a higher temp and one for downstairs you use normally and vice versa at night for this to work.

[StarfishKey]

The answers to this will be really random. Do you have trees shading the house? Are the windows well-insulated? Do you have black-out curtains that you will keep closed? Is the A/C unit itself shaded? Is the roof white? Are you planning to keep the filters clean and all the vents open? Does the house have high ceilings so the heat can rise out of the living space? Will you be running fans in the house?

Moreover, what if you have a 1-story house that is stilt? You get better breeze under the house, and in the Winter better ventilation if you open the windows such that you may not need to turn on the air.

Scientifically, it should not make any difference. The air 10ft higher in the atmosphere is the same temperature, and the sun is equally intense. Buy whatever house you want. Choose a house that is well-built, and do any work necessary to make sure that the A/C is efficient and well-maintained. 1-story or 2-story, if the sq footage is the same, the variables are the same. Your costs are going to vary WAY more, if you're worried about money, with things like wind insurance, hurricane damage, neighborhood crime, taxes, etc. There are many sites online that detail how to keep A/C costs low - buy the best house for you, and then follow those recommendations to keep the cost reasonable. If you want the house to stay at 65 degrees all the time, don't buy in Florida and save plenty of money that way. The $1000/month people have an inefficient house, and a desire for Northern Fall temperatures year-round.

[smarino]

Heat rises. Keep that in mind, especially in winter (what winter?). So simple physics says that a 2 story home will be more costly to cool than a 1 story home, especially an older home w/ less insulation. Shade, and the home's orientation w/ the sun, will also have an influence on a home's electric bill, along w/ factors like the A/C unit itself, diameter of ducting, type of windows and coverings, type of roofing, etc. We had a 2 story home in Galveston, and it was considerably easier to cool the bottom of the home than the top. We had coldish winters there, and the 2nd story was always warmer than the 1st story. In Daytona, we replaced our old, leaking A/C ducting in a mobile home w/ new larger diameter ducting, and the home was a lot easier to cool. This job is easier and cheaper to perform in a mobile home because you can get under it to work relatively easily.

Getting the hot air out of the home is important as well, so attic insulation and good venting will save you money. Efficient home heating and cooling requires good design and quality materials. A solar water heater should be required by law in all new home construction in Florida and most of the Southwest, similar to Hawaii's 2008 law. In this state, it's the humidity that makes you feel so uncomfortable. I've always wondered if dehumidifiers and fans would help on a light bill by letting the energy eating A/C work less.

[StarfishKey]

Originally Posted by smarino

Heat rises. So simple physics says that a 2 story home will be more costly to cool than a 1 story home, especially an older home w/ less insulation.

Getting the hot air out of the home is important as well, so attic insulation and good venting will save you money. Efficient home heating and cooling requires good design and quality materials.

You kind of answer your own issue, though. Yes, heat rises. But if you have high ceilings, good circulation, and a good vent system to allow the heat to escape, having a second story will not affect cooling costs much at all. And if the home is well insulated, has a light roof, has some shade, etc. etc. etc. so it's efficient... then there shouldn't be so much hot air to rise up to the 2nd floor anyway.

The thing you have to worry about is the air that touches your skin, not the air that is up against the high ceiling. So if the lower air on each floor is cooler than the upper air, plus you have a fan on you, plus you have a means for the hottest air to escape, then it does not cost that much to keep yourself cool. You don't have to make the ceiling air feel like 75 degrees, you just need to keep your skin down near the floor feeling cool. Additionally, small changes like eating less, cooking fewer hot foods that heat the home - especially with hours of high heat cooking, and drinking plenty of iced drinks or eating frozen fruit snacks, plus wearing less clothing, all will keep you feeling several degrees cooler without having to pay anything more to lower the thermostat. Plus, those are generally healthy things to do anyway.

As an example, I have lived in both a 2-story home, and a 1-story home, in SFL - both of which had roughly the same total square footage. Both had the same level of insulation and efficiency. Both cost me almost exactly the same to cool and heat. So I am speaking from experience. The 2nd floor I lived in did not feel significantly hotter than the 1st floor - the only thing that affected the temp of rooms much was whether they were exposed to direct afternoon sun, and whether or not I had the windows in such rooms sealed off with black-out curtains pinned to the frames so the air could not escape, and whether I had a fan running in addition to the A/C. The same was true of heating, in the brief periods when that was needed. So a downstairs room that was exposed to intense sun felt virtually exactly the same as an upstairs room exposed to the same sun, and a downstairs room in the shade felt about the same as an upstairs room in the shade. I did all of my work upstairs, and also slept upstairs (I like sleep temp to be cooler than daytime temp) and I never had to crank up the A/C to work or sleep there. When I came down, the downstairs felt perhaps 1 degree cooler, but with a fan on me, I actually felt colder upstairs than I did downstairs, because fans should make you feel 2-3 degrees colder than what the air temp actually is.

A better made house is cheaper in all respects, not just cooling, than a poorly made house - except of course in purchase price. But if you can manage it, I think the peace of mind is worth it, since you not only need the house to be efficient, but also sturdy against water, pest, and wind damage, free of mold, qualifying for low hazard insurance, etc. etc.

From my experience though, there is no appreciable difference in cooling or heating costs for a 2-story house vs. a 1-story house. And I think the science bears that experience out. If you have especially low ceilings, like in a trailer, this might not be the case, but for a typical house, there should be no problem.