Cooling issues on the top floor - HVAC issue
Hello, I bought my first rental property in December of 2016. It is a 3 story townhouse here in the Baltimore area built around 1900. I am having issues with the A/C cooling the entire house. The 3rd floor is noticeably warmer than the 2nd and 1st floors. The thermostat is on the 2nd floor and is set to 72. On days where highs are in the 90's and lows are in the 80's, the 3rd floor is about 8-10 degrees warmer than the 2nd floor. Also even the 2nd floor has been only getting down to 76 when the thermostat is set to 72.
The A/C unit is 17 years old. One month ago I had the Freon charged as the levels were low hoping that this would get the unit through the summer. It still has not been able to cool the house adequately.
I am looking for advice on figuring out why the 3rd floor is noticeably hotter than the 2nd floor. Is replacing the unit with a larger one the best option here since I already had this unit charged/had the coil cleaned?
Thank you
Most Popular Reply
Actually, heat doesn't always rise. It does go from a warmer place to a cooler place. (Did you ever open the attic access in the summer, and feel the hot air come down on you?)
When you meet the HVAC guy, talk to him about maybe installing a separate unit for each floor. It is a big investment, but you will have improved the property greatly, and enhanced it's value.
And, ask him to do a cooling and heating load calculation to determine what size equipment you need. Otherwise, you are just guessing at what size you need. I bet the equipment was never properly sized right originally.
(I am a retired HVAC contractor and I used to teach it at a vocational school in the evenings.)
On hotter days I tend to keep the fan running on my unit to keep the air circulating which keeps the temperature more even throughout the house. Also use ceiling fans and other fans to help circulate the hot air to the return vent. Beyond that you should consult with an HVAC professional since you can't get down to your desired setting on the thermostat level.
Hi Ian, thank you, I will keep this in mind. I am meeting with an HVAC company this afternoon to get their opinion. Do you have any recomendations for HVAC companies in the Baltimore area?
Look at your attic insulation thickness and R-value. As we know heat rises from the other units and naturally the top unit is warmer or colder based on the seasons. This has more exposure the exterior conditions. If your insulation is low then this allows heat into the unit. I would get your insulation to an r-50 value. I would start at the unit and have it looked at.
That is a good point, I hadnt thought about the insulation keeping the heat out as well. Upgrading it would be difficult, does that require tearing up the dry wall to replace the insulation? That would not be possible with tenants occupying the unit
Also, would a whirlybird roof vent make a significant impact? It is a flat roof with no attic.
Ugh, I'm having bad flashbacks when I was a tenant living on the top floor of an apartment complex. I had my own a/c, but it was insanely hot all the time because the sun beat down on the roof and the complex refused to do fix the unit. They refilled my unit with more Freon about 1x/week and called it "good". Not, hmmm...there must be a major leak somewhere. I moved out before the next summer started over that issue.
17 years seems pretty old for an HVAC unit. Speak to a professional and/or supplement the a/c with an in-room a/c or window unit.
The whirlybird vents are for attic / crawl spaces like you see in a house. If you have a flat roof, then all your insulation is in one place, right under the roof membrane on the outside of the building. Adding insulation to the under side of roof (above ceiling) isn't really feasible without making a big mess. When you re-roof add more insulation at that point. Solve the problem at the ac unit and the thermostat.
@Greg S. I had the same issue with a few of my rentals. What typically has happened is that since the homes are very old, the ductwork was designed for heat only. Another common issue that I face is that the HVAC is not the appropriate size for the type of ductwork that is installed. In a nutshell, sounds to me like it's a similar type of ductwork issue that I faced and most likely you'll either need to upgrade the ductwork throughout the whole house, put in a separate system coming from the attic to the top level (dual zone is quite expensive though), or you could just provide your tenants with some window units (which is what I did in one house and they were ok with that).
Anyhow, I would be happy to give you the info of some HVAC guys I use, just shoot me a private message since I don't think I can post their contact info on the forums. (Anyone else that needs their info, just shoot me a PM as well)
i've also heard of dampeners being put on some of the basement and up word so that more flow goes towards the top level. I've never done it, but I know it could be done on some houses
Jim, I just had the roof done and did not know to ask about this insulating layer! aw man if I only knew.. Any other tips on this situation? I am thinking to get a larger A/C unit than the one I currently have that way more cool air is being pumped in. I am not sure that this is the best option though at this point
Heat rises and I would be surprised if the top floor wasn't the warmest during the hottest days of the year. Could always supplement 3rd floor with window units or fans and make sure hot air is not accumulating in the attic.
Actually, heat doesn't always rise. It does go from a warmer place to a cooler place. (Did you ever open the attic access in the summer, and feel the hot air come down on you?)
When you meet the HVAC guy, talk to him about maybe installing a separate unit for each floor. It is a big investment, but you will have improved the property greatly, and enhanced it's value.
And, ask him to do a cooling and heating load calculation to determine what size equipment you need. Otherwise, you are just guessing at what size you need. I bet the equipment was never properly sized right originally.
(I am a retired HVAC contractor and I used to teach it at a vocational school in the evenings.)
@Greg S. one other thing that has not been mentioned that can contribute the the top floor being warmer is the attic not being vented. Though additional insulation can help, if the attic is not vented super heated air can warm the insulation and it will act as a blanket on the rooms below. Properly venting the roof can allow this air to move out naturally and the insulation can do it job. Good luck.
run a load calculation on the house to determine size of unit
but you also need to look at the air flow going to the 3rd floor and where it's coming from
If it's coming from basement 3 floors is a long way to push air going up
Not going to do any good to increase size of unit and duct work won't handle it
The more bends in duct the more restrictions
If you get enough air to cool it there will be way to much to heat it
Flat roof doesn't give you many options
Hate to say it but window unit might be an option
another thought is zoning
Tstat AND damper for each floor when you install a new unit
Might be able to put damper in old duct just depends on size,shape and accessibility
Duct sizing is still important
Return air is important if doors are able to be shut
Spray foam insulation to the attic.
#2 Multi-Family and Apartment Investing Contributor
- Rental Property Investor
- St. Paul, MN
- 3,749
- Votes |
- 3,106
- Posts
#2 Multi-Family and Apartment Investing Contributor
- Rental Property Investor
- St. Paul, MN
Some good tips here already. One thing I didn't see is that you may need more cold air returns. Also if you close the interior doors make sure there is at least a 1" space from the floor to the bottom of the door. Zoning the house is also an excellent option.
For now, what you might do, is just put in window units in the top floor units who are suffering, and just eat the cost until the next lease renewal.
As soon as possible, though, I'd put them on separate meters and put in window units. Let them pay their own electricity and control their own coolness according to what they want to spend.
As an example, I just moved into a rental apartment myself in a low income senior building, where air conditioning is not supplied in San Jose, CA, where it gets hot in the summer.
I am on the top floor, which happens to be the 2nd floor, which of course, is hotter than the first floor, since heat rises.
The problem with the place I live now, where no air conditioning is supplied in any of the units, even though we pay our own utility bills, is that the tenants simply open up their apartment doors to the main hallway, which is air conditioned, in order to cool down their apartments. This destroys any fire walls that the building is designed to keep in place. Tenant units have fire standard doors to the hallway, but if they're propped open - the fire would not be contained.
It's up to me to get an air conditioner if I want to be cooler, according to the landlord, but I regularly prop open my door, just like my neighbors do, in order to stay cool. Whereas, if my landlord provided an air conditioner in my unit, I'd actually use it. My apartment only has sideways-opening windows or a sliding door to my balcony. These require expensive air conditioning options, which I can't afford.
So, if they are ever hit with a lawsuit because of fire damage or death due to tenants leaving their doors propped open in order to get cool, especially when there are heat advisories, in a building where they know their tenants can't afford an alternative - meaning they knowingly created the situation - I think they'd be seriously screwed.
So, to limit your liability, and your costs, I think you should first at least give them the option to cool themselves down with an air conditioner you provide. If they decide not to turn it on, that's then their decision. And as soon as you can, meter all the units so they are paying their own utility bills. Most people know that cooling costs will be higher in upstairs units. If not, they'll soon learn this truth.
i have several row homes in the city and it took me a few before i was able to tweak the systems to better overcome this issue. The flat roofs and lack of space between the roof deck and the ceiling creates a hot zone down a few feet from the ceiling. The key for me was having a system designed to handle the load and having a correctly sized return on each floor. The 3rd floor return must be high on the wall or in the ceiling to recirculate the hottest air into the system.
Do some reading on basic HVAC design and you will learn that a larger system doesnt work better due to the fact that is does not run long enough to adequately cool the air and remove the moisture that makes you feel hot. A large system runs in short burst instead of running for longer cycles. I ended up going with a better system that can run at multiple speeds depending on the load its managing. This type of system will operate like a 2 ton a times and a 3 ton at other times due to the way its designed. Another way to help is to close down some of the floor registers so that more air is pushed upstairs where its needed.
In the end its difficult if not impossible to overcome poor system design and a unit that is 17 years old will not help that.
What color is your flat roof? If its new they should have done it in silver coating. If your roof is black you will be fighting off a lot more heat than you need to.
@Russell HolmesThe return in on the 2nd floor along with the thermostat. Adding an additional return to the 3rd floor seems like it would help, but that is very invasive and I have tenants currently living there. Good idea and I think it would help, but not sure that it is feasible while it is occupied.
@James Barnhart What did you mean by a separate unit for each floor? Are you talking about ductless units for each floor?
@Kevin O'Donnell The house has a white granulated torch down roof, so it should be reflecting heat pretty well
@BOB CRANEY I think adding a return to the 3rd floor would work well, but it is an occupied unit, so it would be rough on the tenants. What has your experience been on adding returns? have they been in vacant or occupied units? How much cost would that add do you think?
I suggest considering a separate HVAC system for each floor. I do not know what your building looks like, so I cannot suggest a ductless or central system. That os for you to discuss with your local HVAC contractors. Apparently you have a separate tenant on each floor. Even if you don't, you will be better able to maintain the temps you want on each floor, that way.