Top apartment gets really hot

11 Replies

Last year the tenants in the top floor of my Multi family home had a lot of trouble with the heat. It was like they were living in a sauna. There's no central air, they just have window AC's.

Can someone please give me recommendations as to what I should do? Should I have someone cut a hole in my roof to add an Attic fan?

My master bedroom is in a loft and we have the same issue. The rest of the house will be cool but there was a major difference as you walked upstairs to the bedroom. We installed skylights that open and that's helped us out alot.

What kind of attic you have? and is your insulation proper?

I finished a attic that was unbearable in the summer, and before we finished, we sprayfoamed the roof the deck and it made a huge difference. The original fiberglass were not doing its job.

it's a really old house, the third floors ceiling is more like a drop ceiling with not a lot of insulation

I'd consider upgrading to a zoned AC system, if it's financially and physically feasible. Typically this problem occurs when you have the thermostat on the main floor, where most of the air flow is needed. The unit shuts off before the upstairs is fully conditioned.

The above suggestions are good too. Anything that allows heat to escape will improve comfort. An operable skylight will do just that, but you'll lose most of your cooling efficiency as you blow cooler air out through the top of the building.

Make sure the attic is ventilated well, if your living space is that hot, what is all that heat doing to your shingles? Your attic floor should be well insulated to keep heating / cooling costs reasonable. Even if your not paying for them, if it's too expensive or uncomfortable for tenants, they'll up and leave.

My first plan of attack would be insulating the attic floor, then maybe an attic fan if needed. I've seen plenty of homes where the attic was pretty sealed up by people siding over gable vents, so maybe you've got that going on. Most homes are ok with out an attic fan, so I'd be looking for good natural venting first.

I'm guessing that the ceiling in this 3rd floor is not insulated as it was not originally a living space. To make it comfortable you would need to insulate. Talk to some local companies. Most can cut about 2" diameter holes in the drywall and blow in insulation. It's a lot more affordable than pulling the ceiling, insulating, and then re-sheetrocking.

We have a triplex here in OC (albeit a one story) that doesn't have any central AC, just window units. It didn't have ANY ceiling insulation, so a little over a year ago, we put in blow-in insulation and our tenants said it definitely helped. We bought the insulation (the stuff with the Pink Panther on the wrapper) at Home Depot, and when you buy a certain amount you can rent the blow-in machine for free all day. Where a face mask and some clothes you don't care about. You will also need a helper, it's a 2 person job. We've also done this in our own house, and my brother's house. All buildings were built in the 1950s or 1960s.

That is assuming, of course, that your place has an attic conducive to this type of insulation, and you have access to it.

Adding an attic fan, or at least some whirly birds or some other type of vent, should also help. I'd definitely consider it.

@Logan Zanki a little late here. Here are some basic principles for cooling and heating.

1) Seal the building envelope before you do anything. If you have a hot attic and every plumbing penetration and electrical box is allowing air in and out it's very hard to keep the place cool in the summer and warm in the winter. Get an energy audit. They will do a blower door test and often local utility companies subsidize it so it's not very costly. This will show you all the leaks to seal. The best approach is to do your sealing first so it will find the not so obvious ones..

2) You want the attic ventilated and the living space insulated. The roof keeps the insulation dry but the space between the roof and living area should be kept as close to outside temp as possible (lots of ventilation). You also want to make sure that there is no insulation that traps hot air and bakes your roof. People argue that they want a hot attic in the winter because it offsets heating costs. In fact it causes ice dams on your roof. The hot attic melts the snow and it runs down over the cool eves and freezes. The water and ice then backs up under the shingles and causes all sorts of havoc.

3) Not sure what you mean by attic fan. Some people understand this to be a mechanical devise that aids in moving air so that item 2 above is done (we'll call those attic power vents) To some people it's a large fan that pulls air from in the house and ultimately from outside and pushes it into the attic (we'll call those a whole house fan). In most cases an attic power vent is not necessary. In most cases the proper placement of vents will create a natural convection which will achieve adequate attic ventilation. Usually you just need more vents as in days past most homes attic are not vented to current standards. Eve vents, gable vents, roof vents, ridge vents all can be used for this purpose. Whole house fans that pull outside air into the living space and move air from there into the attic were often used in past because they are very inexpensive to use. Whole house fans only work if you have adequate attic ventilation because the air cannot be exhausted without proper attic ventilation. Whole house fans are usually huge energy wasters in the winter. It's very hard to seal and insulate that 2 ft square hole in your ceiling that all you warm air now wants to leave out of. It requires deliberate planning to do a whole house fan correctly.

I would think that if the attic is properly sealed and vented then your window AC units should be able to keep up. One thing to check though, most are rated for the size of room they will cool. The smallest units will barely cool a closet so you should also look at that. If you don't still have info on the AC units most have a BTU rating, get that and compare it with those on sale at the big box stores. It may not be totally accurate but if your units are too small that would figure into the equation.

thanks for all of the tips. I'm going to inspect the attic this week and mostly put insulation down. Then I'll look in the vents, but if I do the vents won't it drive up the units heating bill in the winter because the attic will have the outside air?

Three things come to mind: ensure the roof/attic area is well-insulated (as a corollary, if the roof is flat, what color is it? consider high-albedo (white/light color) paint). Second, install regular ol' ceiling fans if possible, these go a very long way at not much cost. Third, wall-mounted A/C, I think Mitsubishi has a line of them.

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