Central AC - a good investment? or not?

[ToomuchStuff]

What size unit did you buy? The biggest portable one I have seen, is around 14K btu. That is only rated for (from memory) around 600-800 square feet. If it got real hot, you would be able to cool a large room or part of a house, but not the whole thing. You generally would have to upgrade to a larger window unit for something that might do a whole house that size (24K btu for up to about 1500 square feet).

Are you planning on selling your house soon? (doesn't sound like it, since you said you expect to be in it forever) Do you have the cash to pay for it? The reasons I ask, it I would think you would want an investment, that went up in value. This would just be a home "improvement", that costs, while taking money away that could be invested. You only get the value when you sell. (until then it is a fixed asset, money pit, or a box you live in) A twenty five year old furnace, is getting close to end of life, if it is the style with electronic components. If you have one that still uses thermocouples, then you could get a lot longer out of it. (I live in an area where people still have both gravity furnaces, and 50 year old forced air furnaces)
My dream home (monolithic dome), is different in construction, so that people tend to use radiant heat and buy a window unit, because of it super insulation values (cave like), it requires about 1/2 the btu of a normal place. (cheaper to go with just a window unit, flows as well, due to fewer angles/curved structure) Where your typical box house, you would be needing fans to circulate the air to and from the window unit, or the duct work does it for a central unit. (construction verses efficiency)

[SteveinMN]

The reasons I ask, it I would think you would want an investment, that went up in value. This would just be a home "improvement", that costs, while taking money away that could be invested. You only get the value when you sell. (until then it is a fixed asset, money pit, or a box you live in)

Exactly. An investment has at least a chance/expectation of paying you off at some point.

When we were looking at replacing our windows, window salespeople used the term "investment" as a justification for their prices. Perhaps if every window we had was ill-fitting, drafty, and a single pane thick, we might have made our money back in energy savings if we were prepared to live long enough in this house to die of old age in it. But even by that definition of "investment", for us, it was not a good investment. And it was made all the more complicated by attempting to value touchy-feely factors like esthetics and how much easier it would be to operate the new windows (put a dollar value on those).

I'm guessing there would be research available (on the Web and elsewhere) which would help you figure out how much more or less efficient a portable/room air conditioner is compared to central A/C. You probably could find estimates or guides which would let you SWAG the cost of duct modifications/replacements (or you could bring in contractors for estimates). You might even be able to guess at how often you'd use the A/C based on degree-days or rules like "when it's 90+ degrees outside, it's uncomfortable inside". But even if you could price A/C usage down to the day, is it worth that amount to you? Different people would have different answers.

A twenty five year old furnace, is getting close to end of life, if it is the style with electronic components. If you have one that still uses thermocouples, then you could get a lot longer out of it. (I live in an area where people still have both gravity furnaces, and 50 year old forced air furnaces)

The owner of a 25-year-old furnace would find themselves lucky, indeed, to find replacement parts, especially for those parts more prone to failure, like control boards. Around here, keeping a 25-year-old furnace is taking a real chance. But San Francisco is a different story. So long as it's not unsafe, replacing it is a choice.

It still makes sense to look at costs like comparable real-estate values, how much buyers would add on mentally for adding A/C to the home purchase (almost always a higher number than the real one), the energy costs you do pay, etc. and then to apply those figures to furnaces of varying efficiencies. More efficient furnaces will cost more up front. Except for statistical outliers, no furnace you buy today will last another 25 years. So the question is if there's any semblance of payback on a new furnace and how much that fits into your budget and priorities.

[Tradd]

I guess a lot would depend on where you live and the climate. I grew up in a house with central a/c (built in 1968, a/c installed somewhere in the early 70s), which was somewhat unusual at the time (going by the homes of relatives and friends). But my dad's sister was married to a HVAC guy at the time, so my parents got it cost, which was the only reason they could afford it. The unit was huge and lasted until sometime in the early 90s.

Here in the Chicago area, homes without central air are unusual, unless you're in older construction in Chicago (lots of 1920-1940 bungalows). Here, if you didn't have central a/c, I think you'd have a harder time selling your home. Summers can be hot and humid here.

[Geila]

I should clarify. When I said investment, I meant in terms of enjoyment. I'm not really concerned with resale or financial returns. For example, in our area, water is very expensive and tier-priced. We use quite a bit of water during the dry seasons (which can sometimes be most of the year) so pay a lot for it. But the enjoyment we get from our outdoor spaces far outweighs the financial cost. We really enjoy our gardens every day of the year. Big return on investment.

Enjoying our house so much means we rarely have any desire to travel so we do have a financial savings as well, but that's secondary.

The thing with the AC is that we will probably only use it at most 4 weeks out of the year, and even then, only for a few hours each day. So the enjoyment is very limited. What I need to consider is how miserable I might be if I don't have AC during those potentially HOT days! And measure my investment in terms of misery avoided. For both dh and I. Dh doesn't mind the heat, but he does mind how cranky I get when I'm hot.

[Rogar]

I got central air a couple of years ago after going back and forth between that and a swamp cooler. Swamp coolers use less energy and are less expensive, but require a little more maintenance and I hear they don't work well in humid climates, but have some limits on how much they cool. My basic rules for comfort are that if it's not over about 85 or 90 degrees outside I don't use it and can be comfortable. If it's on, I set it at 75 or 76. I got a newer AC unit that is "energy efficient" and with our weather here I really only need it 2 or 3 months of the year on hotter days, mostly in the afternoon and evening and not at night, so it hasn't added much to my utility bills. I have a smaller well insulated house, which helps. All told, I have considered it a very good investment by making my home comfortable. I had one of those smaller portable room units and central air is greatly superior, although a good window unit might have come close to doing the job.

[SteveinMN]

What I need to consider is how miserable I might be if I don't have AC during those potentially HOT days! And measure my investment in terms of misery avoided. For both dh and I. Dh doesn't mind the heat, but he does mind how cranky I get when I'm hot.

So it's like keeping an old rusty pickup truck on the driveway, licensed and insured for the few times you might need to move something that size. I think most people on this forum would tell you to not keep something you don't use often, especially given the expense (there's not just installing it; there's periodic inspection and running it).

You probably could choose to go to an air-conditioned hotel on the really hot days -- maybe a number of them per summer -- for years and still be ahead of the thousands of dollars it would cost to buy, maintain, and run an air-conditioning system.

[ToomuchStuff]

Along Steve's line of thoughts. Trucks can be rented. An inexpensive, room a/c could be installed for much less then the cost of central air, and you could either pull it out of the window, or sell it locally, and not have possible headaches from lack of use. Just another option.

[idahome]

i could get by with just heat here in the winter and even that i don't turn up very high we have turned on our window ac about once a week mostly just use fans

[JaneV2.0]

We're going through a hot spell (nineties) here in the Seattle area. Like last year, I haven't even broken out the fan. I have (non-functioning) AC and I don't miss it. Being uncomfortable in the Summer makes the arrival of Fall that much sweeter. I would only have central AC if I lived somewhere the heat was relentless and unbearable.

[iris lilies]

We're going through a hot spell (nineties) here in the Seattle area. Like last year, I haven't even broken out the fan. I have (non-functioning) AC and I don't miss it. Being uncomfortable in the Summer makes the arrival of Fall that much sweeter. I would only have central AC if I lived somewhere the heat was relentless and unbearable.

that would be here.
Most houses in my neighborhood, being tall and skinny, have multiple
HVAC systems for efficiency. When we renovated our house 25+ years ago we put in a system only on the third floor to cool that floor and the 2nd floor bedrooms, but we put in vents for the eventual 1st floor system.For years we couldnt have people over for dinner in the summer unless we were outside because inside was too hot. Well, outside is often pretty damned hot, too!

Then a few years ago we installed AC on the first floor and to this day, I still experience it as a luxury. It is wonderful to cme into a cool kitchen after working outside.t

Our dogs ,appreciate it, too. They live on the first floor, and bulldogs need to be cool. Before we got the 1st floor system the cold air from upstairs would drop down into the first that was coolish, but not great. Durng that time we had an older bulldog who was suffering from the heat, so DH put in a window unit just for her, in "her" room. She had cooled air for the last two years of her life.

There are houses here that still,have no central heat, let alng central AC. We just sold a tiny houses that had never had central systems. Guess they went from a fireplace to electric baseboard heat.