Energy audit on the new house

Money goes in, heat leaks out
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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Energy audit on the new house

Post by kevm14 »

A little over a year later, I found myself in the same position of wanting, at the very least, some energy efficient bulbs to replace the incandescents that were all over the house.

So I scheduled an appointment and RISE came out. Unlike with my other house, he did not have enough bulbs to finish the job, and I was planning to perform some of the work recommended to increase the energy efficiency of my new house.

The work I had agreed to performing:
- Air sealing (subsidy covers $750 of the $880)
- Duct sealing, forced air heating
- Attic insulation, add 11" blown cellulose which adds R-38 to what's there
- Attic ventilation, 1 chute per rafter bay (54 total)
- Soffit vents, 4 4x16" vents
- Basement sill insulation, R-19
- Duct insulation, R-8 vinyl-faced fiberglass

Total unsubsidized cost of work: $2,965.70. After subsidy, my cost is $1,662.28.

Now I could do some of this work myself and save some of this cost. But I'm electing for them to do everything that has a favorable ROI, which all of this work does.

Since he ran out of bulbs, and I wanted work done, I had to schedule a technician appointment, which happened this past Friday.

For this appointment, they did a blower door test and a bunch of other things.

Blower door preliminary test results next.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

Blower door start (all results at CFM50): 4,326

This is typical for a 70s house.

With basement door closed (but not sealed): 3,862

I think the target is about 2,111 (after work is performed), if I understand the form I am looking at correctly.

The next work they did surrounded my furnace and hot water heater.

Zero ambient CO was measured in the home with the furnace and hot water heater running, plus everything closed up and the cooktop vent running. This is good.

Even better is the flue gas CO for the furnace was 13 PPM and for the hot water heater was 10 PPM. This is quite good for oil heat (gas can be almost 10x better), which means both burners are operating efficiently. In fact, the furnace efficiency was measured at 82-85% which is good, and the hot water heater at 99%. Not entirely sure what the context of this efficiency is, but the results are good according to the technician.

However.... there is a problem that has resulted in a stop work until the issue is fixed.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

And that problem is the draft performance of the furnace and hot water heater.

Individually, the draft performance of each (when only one is running) is actually good.

But when both are running, the draft performance on the furnace is unacceptably low. The best recommendation I got from the technician (who also called the home office for help) is the way the exhaust connects to the chimney. Basically the hot water heater (oil fired) and furnace (oil fired) both vent into the chimney via separate exhaust pipes.

The suggestion was, they should Y together first, and then there should be a single pipe entry to the chimney. This will improve draft performance due to the venturi effect.

So I will need to call a plumber (apparently) and have that fix performed.

The technicians also had a smoke machine and at no point was there actual spillage from the draft dampers. That means all of the exhaust is staying in the pipe and going into the chimney. But the rate is too slow when the hot water heater and furnace are both running. Even turning off the cooktop vent fan didn't fix the problem.

By the way, they do measurements in what they call worst case, and natural conditions. Worst case is all doors and windows closed (including INTERIOR doors) and all external venting appliances turned on. This makes the draft performance as bad as it can be. It was also measured under natural conditions, meaning interior doors open and cooktop vent fan off. Still failed.

As an aside, this goes back to a (really stupid) argument I remember having at work when some present didn't understand that any time you push air to the outside (furnace exhaust, dryer vent, cooktop vent, bathroom vent, etc.), the air that goes outside is REPLACED with outside air that seeps in the house. Where does this air come from? Everywhere. Cracks, crevices, you name it. Very new houses are so tight they need a specific air exchange system. Older houses always naturally seep enough air in, even with all windows and doors closed.

If outside air did not replace the air being pushed to the outside via the systems I mentioned above, the house would eventually pull a vacuum and all air would be sucked out. Since that clearly doesn't happen, that is proof that the air is being replaced.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

The best solution recommended to me so far is to move the hot water heater to the same wall as the washer and dryer (the wall I'd vent to), and install a power venter in that wall. The grade slopes down there and so does the foundation so there is very easy access to the wall.

Then just run the oil line over, plumbing and electric.

My local oil company said if I did the actual moving, they could do the rest. It's not that I can't do plumbing and electric, but maybe I'd just rather have someone else do it. Probably will cost in the $1200-$1500 range.

That leaves the furnace on the chimney which I really didn't want, but this configuration should pass the draft test and let me go ahead with the insulation job (for another $1500....sigh). And I still think I'd like to do it. The basement gets warm when the furnace is on (air leakage from the ducts and they are not insulated). There's a nice cold draft from the walk-out door. And even the garage is warmer than I think it should be. Heating wise, we are talking about 2,326 sq ft of real conditioned space, another 1,080 of basement and another 576 sq ft of garage. You can see how that is not efficient. Though it means that doing laundry in the winter isn't a winter coat affair, and working in the garage is warmer than outside. I could do a lot to make that a lot better, too.

Not sure when I will actually get to this, as I would obviously need to coordinate with the oil company. Not really interested in disabling the hot water heater for more than 24 hours.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

Took care of some very low hanging fruit.
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There was quite a bit of airflow leakage right at the furnace. I went down while it was on a heating cycle and the basement was definitely cooler.

I used a tape made by Nashua. Serv-Pro left it behind when they did the duct cleaning. It is a great tape and way better than duct tape. It's actually made for ducts.

Appears to be Nashua 324A.

http://www.amazon.com/Nashua-Weather-Pr ... B00D7GE38Y

Damn, $30/roll. Score.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

I had another brainwave while watching an HVAC youtube video. I never bothered to learn about the barometric dampers that are typically installed in the exhaust vents of oil or gas fired heating/hot water appliances. He was adjusting them by targeting 0.01"-0.02" of draft over the fire. The adjustment was a little counter-intuitive to how I thought they worked. When you adjust them to open more when the appliance is firing, the air drawn in decreases the draft over the fire. So the complete elimination of the draft damper would result in the most draft possible. All of the chimney "suction" would be applied to the burner.

So I think I will purchase a draft gauge, likely this Bacharach 13-3000 which seems like the industry standard.

https://www.valuetesters.com/bacharach- ... gauge.html

As usual eBay has better prices than Amazon. I may even use an HVAC supply place like the link above.

But yeah I'll take some readings over the fires for my furnace and hot water heater and see where they are. Then I may check right at the chimney and see what kind of draft it has. I wish I had the readings from the RISE tests.

It is possible that I can delete both barometric dampers and get the maximum draft up my chimney, and possibly pass the draft test without having to do anything else (i.e. no moving the hot water heater and installing a power vent, to considerable expense, not to mention adding another maintenance item).

Also it looks like my furnace damper was set up for a vertical vent; this one is horizontal. I switched the direction of that bottom tab on the damper and also the side the weight is on. I adjusted the weight so the damper is less prone to open for now. The idea behind the 0.01"-0.02" is to ensure the minimum suction over the fire. Less and it could become positive which is bad and more means more heat loss up the vent.
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kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

kevm14 wrote: Mon Jan 20, 2020 12:11 pm https://www.valuetesters.com/bacharach- ... gauge.html

As usual eBay has better prices than Amazon. I may even use an HVAC supply place like the link above.
Amazon. $143.25 (not even prime but free shipping)
https://www.amazon.com/Bacharach-0013-3 ... 072&sr=8-1

eBay. $136.14, free shipping.
https://www.ebay.com/itm/BACHARACH-13-3 ... Swrz9bV1mh

Registered for a Value Testers account. $117.87, including shipping.

I should make a separate topic for this but I think the care-free days of going to Amazon.com, expecting the best price while getting free 2 day shipping are over. As I've said before eBay has been cheaper most of the time and in this case an HVAC supplier was even cheaper. I registered via the "Youtube Steve" account type based on the Youtube channel Steve Lavimoniere Plumbing & Heating who is based in N. Dartmouth, MA, so there may be a discount there. I paid through Paypal so I'm not relying on the security of the site itself, though credit card fraud is easily resolved these days...but I digress.

And yeah, things don't stay the same forever. Stuff always changes. Old habits die hard, etc.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

National Grid sponsored an unprecedented 100% coverage offer on insulation improvements. So naturally I called again because I need to bend over backwards to make this work. I did a virtual audit and they came up with $6,400 of insulation work. My house would greatly benefit from this work. They also sent me another small round of bulbs and surge protectors.

Anyway after a voicemail fiasco, I ended up getting in touch with the subcontractor (this one is out of CT) who would actually serve my area. They are booked until April at this point which is about when National Grid has agreed to extend the contracts. However, I could get slipped in earlier if there is a cancelation.

But more importantly, I asked the "hypothetical" question about whether I have a failure with the draft test, and how much time I have to resolve it. He thought about it for a second and said, well, we could probably send someone out much sooner just to do that. AH! This is brilliant. I should have just asked.

Of course, they are about to shut down the business for 1-2 weeks because of COVID quarantine but I should be getting a call late next week to firm this all up. This is a very good idea. That way we can either decide I pass the draft test (hopefully they wouldn't recheck it later, though I'm not sure what their actual rules are - I'll press that if it's "close"), or maybe most importantly, if it fails, I can take measures to resolve the issue with plenty of time before the actual work. And maybe call them back to check.

Based on last time I may still find out that I need to relocate my hot water heater (because that would be easier/cheaper than venting the furnace based on where it is). And maybe at that time I'd replace it just to simplify some logistics. If it comes down to removing the hot water heater from the chimney, I guess I'd just call to get a quote to install a new hot water heater elsewhere in my basement. Ideally they'd remove the old one and sort of cleanup the old install. There are some options but no idea on pricing or whatever.

I could also call an oil/plumbing place and say, I need to remove one of these from my chimney....which is easier/cheaper/better and what is the method?

I see no way around needing a power venter one way or the other and I'm not a huge fan of that but again, it's the only way. The only OTHER option is to go to a heat pump hot water heater and I am not into those one bit. To recap, the reasons against are:
- They don't last as long. The oil fired ones last in excess of 20 years.
- More expensive to buy (probably)
- Makes the basement colder
- Recovery rate is a FRACTION of what a direct oil fired HW heater can do. Like it's not even CLOSE. Direct oil fired is basically on demand, unlimited HW.
- If the heat pump can't keep up, it falls back to resistive elements which draw big current. This leads to the operating cost likely being HIGHER (despite the energy savings claims), particularly when oil is under $3.50/gal. Electricity only goes up. Never down. This defeats the entire sales pitch.
- I'd need at least a 7kW generator to handle the HW heater because the resistive backup element draws 4500W by itself. Power does go out from time to time. Adding loads that the generator needs to power is going the wrong direction.
- Complexity! We're talking about a hot water heater with a damn air conditioning heat pump sitting on top of it. No thanks.

Those are a lot of good reasons.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

1882 CFM target, no less than 1261. Was at 4092 CFM.
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HW -3.4
Furnace -3.6

Limit -1.75
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Good news: that is a pass!! Not the kind of numbers he expected but a pass nonetheless.

Here are some other specs on the burners. They are both running very, very clean.

Furnace has 5 ppm CO and 80.6% efficiency. These are both good. The CO is very low and I think the original efficiency was rated at like 81% and this thing is probably at least 30 years old.
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Hot water heater has 2 ppm CO (extremely low) and 79.6% efficiency. I would have liked to see the efficiency higher but if it's got build-up in the tank then that could lead to a lower efficiency. Burner itself is running extremely clean regardless.
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He also installed a new programmable thermostat free. Nice.
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To do: Clean out attic area, basement perimeter, add 2nd floor bathroom vent fan. Just fan itself. They will vent to roof. May need to remove knee wall roof insulation but it will only add $50-60 if they do it, so given that the entire job is free probably not going to sweat it.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Energy audit on the new house

Post by kevm14 »

4711 CFM after.
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