Too hot! Landlords, which is better, attic fan or insulation?

19 Replies

We are in the middle of a hot North Carolina summer, and one of our older, C class properties is not cooling properly. 

It is unclear to me at this point if this was an issue before. We've owned this house for nearly 4 years but no previous complaints about too hot or cold. The HVAC is four years new. Previous tenants may have just tolerated it, but I really have no way of knowing. The HVAC people have tried and tried to fix it, and at this point their conclusion is that the unit is now working properly and the final issue is with the house, ie, basically no insulation. 

Now, we do not generally put money into insulating class C rental properties. However, we have to do something as the house will not cool below 80 degrees despite running the HVAC continuously.

The HVAC guy recommended an attic fan because of the very high temps at the ceiling. However, I looked online, and many seemingly knowledgeable people recommend against them, and recommend just doing a lot of attic insulation. 

Its probably going to cost around $800 either way.

Would love to hear your experience on this matter. Thanks!

Some references for those interested:

Follow up question: If the consensus is insulate, which is better, blown or sheets? The house does not currently have any attic access btw. (Did I mention this was a class C property?)

@Vishakha Penney First I would get a second opinion on your HVAC. You air handler may need to have the coil cleaned or the outside Condensing unit may need a good cleaning. I assume that you don't have a leak and that the pressure was checked as this is the first thing they check.

Did they take a temp reading of the inside vents to see how cold the air is from the AC?

If your house was cooling before then it should still be capable of cooling the house.

I have a hand full of Mill houses with next to no insulation and single pane windows and a 2 ton unit can properly cool a 2 bed 1000 sq ft house.

Insulation in the attic should help but your exterior walls still probably have no insulation. There might be someone that can drill small holes and spray foam in the walls.

First thing get someone else to make 100% sure your AC is working as it should.

I have had people who think there house should be 60F in the summer and 90F in the winter, find out if this is the case.

@John Underwood , thanks for your reply. Yes, that was my first thought too...oh it must be the HVAC. Six trips later I'm not honestly sure. The house is hot, no doubt about it. On a 95 degree day, it was well over 80, with ceiling temps of 110 or so. The air coming out of the vents is pretty cold at 65, but the return is warm. What I don't know is whether it was like this every summer before and the tenants just didnt care...

The poor bastards at the HVAC company have cleaned the coils multiple times, checked the pressures, and at their last visit emptied the entire unit of coolant, put in a new pump just in case, and then weighed the coolant back in to make sure there were no contaminants. So, I suppose I could pay another company to go out there and confirm this was all done properly, but given this one company has sent every tech they have and finally the tech manager, I'm inclined to think the remaining problem lies with the house, and my tenant's general tendency to be less tolerant than the last three!

Some older houses in the south have no insulation in the attic nor walls.  I've used blown insulation for the attic in an older (1930) house and that made a TREMENDOUS difference in the heat efficacy/bill.  It was not even close to $800.  I bought the insulation from Lowes, and at a certain amount they rent you the blower free of charge.  I paid a laborer $40 to go into the attic to spray while I fed the machine from the ground.  I was all-in at less than $300.  But that was about 4 years ago.

The tenant at the time said the house was much more comfortable and the heat bill was lessened by 1/2 to 2/3.  I would have blown insulation in when I bought the house, but I never went up into the attic to see -- the access panel (not door, but yes, panel) in that house is about 18"x20", and I didn't want to struggle with squeezing through.  Now, I make sure every house has insulation in the attic.  Heating costs will be insane without attic insulation.

Regarding the whole house attic fan: I had one installed in a different property that did have adequate insulation.  I had never been in a house that had one before, or at least not to my knowledge.  Once I had one installed in my rental, I have to admit that with that fan on high and at least one window open (preferably at least two, one front and one rear) the house stayed very comfortable through a slight rehab during turnover in the hot and humid southern summer, without using A/C. 

If you decide to install an attic fan, I recommend paying extra for one that is proven to run quiet.  I didn't pay for that feature, and on the highest setting that thing sounds like a plane landing in the hallway.  The lower two settings are not so bad, but the highest setting is unbearable.

The fan would help, but not as much as insulation. The fan will pull air out of the attic, which will pull the cold air out of the apartment (it will be leaking everywhere ie doors, windows, wall outlets, pipe penetrations, etc ) and pull more warm air back inside to make up for it. As stated above, put in some blown in, it is cheap and easy.

Nothing beats insulation. I would even do the walls. If it's cheap utility bills tenants will want to stay but not if they are high.

The attic fan will only help depending on how the attic system is built. If there are no ridge or soffit or gable vents then the attic fan will suck out the air inside of the house and pull in our lovely, humid 95 degree NC air constantly and try to cool it off. No fun. I would look at blown in insulation. Spray foam seems out of the budget, but holy cow it works. My house we just sprayed the attic only, and with no HVAC on it's only about 80 degrees on the hottest days upstairs. It is probably not cost effective on this property, but I was also able to downsize my unit downstairs by 1 ton, and the unit upstairs will hardly run once it gets turned on. If you can't tell, I'm pretty excited about the spray foam lol. 

But just get it blown in. Also look at caulking wherever there are penetrations going to the attic from the ceiling. Light boxes, vents, etc and make sure to seal up between the box and the drywall. This will help with losing air to the attic via the stack effect. Good luck

Are the returns in the attic? If so, and they're not insulated, you're going to have a terrible amount of heat loss (and condensation to boot) right there. 

If it were me: I would find the best HVAC company in your area, call them up and ask specifically for their best technician to come out and assess your system. Before I spent any money. 

I would also call an insulation guy out. Get his opinion and an estimate. If you decide to insulate vs installing an attic fan you can DIY. Rent the machine from Lowe’s and blow the insulation in yourself. It’s not hard to do.

We just had insulation blown in and the guy who gave us the estimate explained exactly what needed to be done, but it was a lot of insulation so we chose to have him do it.

Note: blowing in insulation creates a huge mess. Have your tenants cover everything or put the access in an out of the way spot.

Days after we had the insulation blown in temps hit the high 90’s here. The house stayed cool yet everyone we knew said their ACs had a hard time keeping their house cool. It really does make a huge difference.

If it’s the same cost as an attic fan I think insulation may be the better investment. No moving parts like a fan and it will make the house more comfortable in both hot and cold weather.

@Vishakha Penney it seems to me the AC unit could be undersized, assuming it is operating properly. Another thing to consider is that windows are a major source of temperature loss and sun can heat up the property through the windows. Something as simple as sun blocking curtains or blinds can help keep a property cool. Window tinting any windows with sun exposure can help too. 

Does the attic have proper venting? There should be vents under the soffit for air intake and vents on top of the roof for exhaust. The high ceiling temperature is an issue, so I would not discount the need for an attic fan. Maybe the answer is a fan and insulation.

I know you don't want to spend money, but you need to keep tenants happy. Also keep in mind if the AC is running continuously, that will lead to higher AC repair costs. Either way this will cost you. It is always better to fix a problem.

@Randy E. , thanks that is super helpful. It sounds like insulation is the logical place to start. We weren't actually thinking a whole house attic fan, just the kind of attic fan that goes in the roof and pulls air out of the attic only. But it sounds like the consensus is that even those are secondary to insulation and sealing the attic space.

@Joseph Druther , thanks, that was definitely one of my concerns. The attic has a few soffit vents, but fewer than is code now, and no ridge vent. There is no attic access at all to the house (lovely and weird, I know) but still, the attic is probably under passively vented. Thanks for the advice, blown in it is!

@Michele G. , thanks for the tips, especially about the mess! Contractors never seem to mention these things, and this tenant is kind of OCD, that would drive her nuts if she didnt know to cover..!

Originally posted by @Vishakha Penney :

@Michele G., thanks for the tips, especially about the mess! Contractors never seem to mention these things, and this tenant is kind of OCD, that would drive her nuts if she didnt know to cover..!

 I was furious. The access was in my bedroom and every surface was covered in a fine dust. I even had to wash the walls and use an air purifier. I wish they had used a plastic wall to contain the dust. 

Also check with your utility company. I don’t know how it works with rentals, but some give rebates when you add insulation. 

@Michele G. , yeah that’s crazy. Regarding the rebate, great point! I actually found a contractor through the power company website who does work that they will then give a $250 rebate on, so that’s pretty awesome. Actually thinking about doing it at my house too! ;)