110 year old house with hot attic with 3 year old AC -

3 years ago

We have an old house - 110 years. 2 HVAC systems basement and attic. in basement. Slate roof. We are trying to decide if we should get foam insulation. We thought the old AC was not working properly, however, the newer system is not cooling appropriately in the summer due to high heat levels and poor ventilation in attic. I am trying to decide should I add blown insulation to attic floor and improve ventilation with fans and new soffits or encapsulate the attic with spray foam. Spray foam is the most expensive but I think it will solve the problem of high temperatures in the winter and better insulation of the attic for cold winters in Ohio.

Should we go with foam insulation? or should we try something else>

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Comments (10)

User
3 years ago
I would suggest looking into radiant barrier. Also check the duct work for leaks and closed dampers. Then check to see if the HVAC is properly sized. I've lived in houses with HVAC in hot attics and the systems that worked just fine.
millworkman
3 years ago
Has anyone done an inspection and run the numbers to make sure the ac system installed is the right size for the home?
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Thanks for all the feedback already!!! We're really trying to stay away from the mini-splits or ductwork from the basement up into the original floors--all for aesthetics sake. For having all of the original windows, this house really is well-insulated and stays relatively cool on the first floor throughout the summer...the house has six bedrooms and we have three kids, so we really need the central A/C upstairs because the window units are getting very annoying since all the rooms are now used. Glad to hear that Lennox isn't terrible--we like that company, they're local, and well-established/respected. Can't wait to hear how the other bids come in. I'm fine with having ductwork in the ceiling--I'm trying to keep a nice balance between the integrity of the house and our comfort as a young family. That doesn't offend me like some other changes might. The attic is GIGANTIC and the ductwork will be kept off to the sides, so if we ever get a chance to put our dream rec-room in up there, short knee-walls would cover it. Honestly, I'm pretty confident that with the two open stairwells the front third and back third of the house should be cooled pretty well. The one room in the middle of the downstairs is our living room, so if that doesn't get cold enough, we'll go with either one window unit or one mini-split. My parents have them in their 50's ranch, and while they love them, I just can't get over the look... Thanks...any other info would be much appreciated!!! -Sarah from Albany
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Seabornman
3 years ago
The slate roof could be an issue. Slate is usually nailed to spaced boards and there is a certain amount of air that passes through. If you search for "slate roof spray foam" you'll get many opinions on best how to insulate such a roof.
res2architect
3 years ago
Its dangerous to offer opinions without seeing the project but, in general.in this kind of climate it pays to seal the attic with spray high density foam. In general, in a cold climate HVAC equipment & ducts don't belong in a ventilated attic.
mike_home
3 years ago
Houses built 110 years ago had no insulation. How much insulation is currently in the attic and is it in good shape. I am not an spray foam expert, but I would caution you about spraying the roof deck given that you have slate tiles. You need to consult with someone who has actually done this and see the results after a few summers and winters.

I suggest adding blown in insulation to the attic floor. You want a minimum of R30 insulation, ban ideally close to R40. You should add soffits and vents as needed. The duct work in the attic should an R8 rating with tightly sealed joints.
roarah
3 years ago
There is a industry wide issue with copper pipe conduits due to acid leaking from the insulation and corroding the copper and thus causing refrigerant leaks. The issue is prevalent in systems installed between 2017 and 2018. I know this from first hand experience.

After draining my system and weighing the refrigerant in my 2018 system to trouble shot a similar issue the issue was uncovered and after having my copper replaced and insulated with a new product and my refrigerant replaced it is cooling at a fraction of the cost and cooling to set.

You might ask the company that installed your unit to look for leaks and ask about the copper insulation specifically.
ceilsan32
3 years ago
Is your attic finished, or do you have only boards over the floor joists. Homes of this age can be balloon construction, meaning you could drop a line from the attic and it would go through to basement level. I'm not a pro, but looked into foam injected (via outside) for a mid century home and was told that if foam was used, it would fill up wall cavities, making access to future electrical work very difficult. I opted for blown in cellulose by a highly reputable company who filled all voids to avoid heat loss, and installed a sealing attic entry door with vertical sides to preclude movement of cellulose. You might want to look at some DR. ENERGY videos before deciding on best type of insulation.
User
3 years ago
When I had A/c and a new furnace heater installed in Silicon Valley, CA, I was required to have a load calculation....J load?....Does your area require something similar?
kevin9408
3 years ago
before you do anything hire a professional to conduct an energy audit that includes a blower door test.

110 year old house with hot attic with 3 year old AC -

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