Improving Energy Efficiency of an Old House
I have a complicated situation that includes a hot water tank, heat pump, stack effect, insulation and Radon.
I live in a house that is about 125 years old and an energy efficiency disaster. And very limited funds to fix things.
Its a single floor with 2/3 unfinished basement and 1/3 dirt crawlspace (uncovered dirt), balloon framing so gaps from basement to attic (hence stack effect losses). Partial traditional roof, part low slope roof (over the dirt crawlspace part of the house). Walls have loose fill insulation, basement is not insulated, brick foundation and attic has some animal trashed fibreglass with shredded kraft paper, about R8 according to the energy audit. About 15ACH50 with most of the leakage coming from the crawlspace.
I got my hands on an Air Things Radon tester form the library and have had some interesting results. Before the heat was turned on (last month) i had about 36 Bq/m2 upstairs and about 90 Bq/m2 in the basement. Once the heat was turned on (furnace is in basement, high efficiency 95% natural gas) i got about 60 Bq/m2 basement (iirc) and 32 Bq/m2 main floor.
All tests are for about a week
So in the here and now i am looking at insulating and i also need a new hot water tank as the one i have is rusting (anode was never changed to my chagrin). I looked into a heat pump water heater but they are very hard to find (i am in Canada about an hour south from Toronto). The only one i can get is about $3700 after taxes from Home Depot and they refuse to install it and say they cannot get maintenance or repair parts. Also direct vent hot water tanks are unavailable from the half dozen places i have called.
So my options are replace the atmospheric chimney vent (metal pipe chimney) or power vent. Everyone tells me to go chimney vent, its not lined but its also not a brick chimney. Powervent is also commonly available.
As for insulation, been trying to get quotes but nobody wants to send the quotes, its a weird happenstance that i am working on I did get one who said 5K for header insulation for basement headers and attic (i am wary of insulating the brick foundation from the inside).
Also i have gotten quotes for a heat pump to replace the 20 year old central air they tell me cannot be recharged, $8000 + tax.
Finally we have a government incentive program here that i am working to get the details of but will pay $6500 for a heat pump, so after taxes i would be out $2500 for the heat pump.
In the end if i air seal Radon will probably be a lot higher and an HRV is not in the cards at the moment due to cost. So one can argue that an inefficient hot water tank would be a good thing (i have a heat pump dryer so no radon removal there).
Thoughts?
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The radon is coming out of the soil below the house. Sealing the basement will help keep it out.
It all comes down to cost, and my lack of funds to finance mitigation.
Ideally i would dig to full height then put down a concrete slab, air seal, heat pump water heater, heat pump furnace/AC, insulate attic, insulate walls, upgrade windows and HRV.
I can afford a cheaper one of the above (and rent a powervent or atmospheric vent water tank).
I'm not in Radon land, so can't help you much there, here is what I've done on a similar balloon frame house.
You identified the major issues, the chimneys in the walls. These were fire blocked at the basement, at each floor and in the attic. Watch also the interior walls, mine were fully open without any blocking in the attic for these either. The blocking was sealed then with one of the two part spray foam kit and dense packed the walls with cellulose. These along with some new windows and doors brought the place from 20ACH50 down to 8ACH50 and also made a place where you could not sit by an outside wall in the winter to a perfectly comfortable place.
Generally air sealing will make radon worse, so I think you'll have to deal with that eventually. The one band-aid that has come up here that is effective is to install an ERV/HRV with a large stale air pickup in the basement and crawlspace. This exhausts the air with the highest radon levels without much of an energy penalty. It also won't de-pressurize your place which sometimes can draw even more gas from the soil. It also brings in fresh outside air which is also helps. At least for your crawlspace, I would look at proper radon mitigation with a poly on the floor and up the walls and venting.
The more you tighten the place, the harder it will be to use atmospheric vents. I would switch to direct vented units (powered or unpowered) to save you issues down the road.
It is a shame the heat pump water heaters are so pricey up here, if you are near the border, you can pick one up in the US for much less.
Well done bringing 20ACH50 to 8ACH50. I have about 15ACH50 here. Much of it from the crawlspace.
I have gotten some 6 mil poly that i could put down, though i am not sure how much it will help but i am pretty sure it will not hurt.
Just like no one has heat pump water heaters no one has direct vent either. In fact almost no one has even heard of them. My options are atmospheric or power vent.
The HRV is a nice idea, if i can swing the cost someday i would very much go for that.
I do live in radon country Utah. Heat pumps however are not really a thing here either.
Sealing is said to be good, but it isn't even talked about as being a true mitigation. Here it's a radon vent (3 inch PVC with a van venting outside per EPA standards).
Since it's a gas that penetrates and your foundation will eventually have cracks that weren't there before or unbeknownst to you, I'd think a mitigation system is more worthy a reducer than general sealing off effort--all else being equal.
I am assuming my Radon levels are fairly high but are being kept down by the hard to repair air leakage due to the foundation design and balloon framing.
In summer my dehumidifier runs overtime to keep the basement at 60%, otherwise everything metal starts rusting.
ah, you're in quite the pickle with your house there. sounds like it’s got charm but is also a bit of an energy-guzzler, eh? 😅 first off, the radon levels you're talking about are definitely a concern, especially with your basement situation. that uncovered dirt crawlspace is likely a big culprit here. but before you go sealing everything up to improve insulation, you’re right to worry about radon – sealing can trap it inside, and without an HRV, that's not great. 😬 so, for the hot water tank, if the anode's gone and rust is showing, yeah, it’s time to get that sorted. power vent vs. chimney vent is a tough call. chimney's old-school but straightforward, while power vent is more efficient but yeah, more common. given your funds, might lean toward what's more affordable upfront and easier to maintain, right? 🤔about the heat pump, that government incentive sounds sweet! dropping $2500 after the rebate might sting a bit, but if the old AC is on its last legs, you’re gonna have to bite the bullet sooner or later. plus, heat pumps are a solid move for energy efficiency in the long run. 💰 insulation quotes being a ghost town is frustrating, but $5k for just the headers and attic seems steep, especially if you’re wary about the brick foundation part. sometimes, though, spending a bit on proper insulation can save a bunch on heating. it’s a balancing act. 🏡 now, the radon and stack effect. before you seal up for air leakage, might want to tackle that radon issue head-on. maybe look into radon mitigation solutions that don’t break the bank? some DIY radon reduction methods can be effective without being too costly. 🛠️ if the heat pump water heater is a unicorn and no one's keen on helping with install or maintenance, might have to let that dream go for now. sucks, but what can you do? 🙃 in the end, it's like juggling with too many balls, trying to find that sweet spot where you don't drop the important ones (like radon safety and not going broke). gotta prioritize what’ll give you the best bang for your limited bucks. 🤹♂️ it’s a tough spot, but taking it one step at a time and weighing what’ll save you most in the long run is probably the way to go. keep chasing those incentives, and don't shy away from second or third opinions on those quotes. good luck! 🍀