Re: Digest for seattle-home-electrification@googlegroups.com - 2 updates in 1 topic

[Steve Gelb]

I think that the trickiest thing and concern that I've heard is that when you convert a ducted system from gas to HP you need to push more air through the ducts since it's not nearly as hot as the air from a gas furnace.  I've had two friends comment that they are somewhat bothered by the noise from the air running through the ducts almost constantly.  

As for back-up heat.  I don't believe that new heat pumps in our climate should need it.  The installers recommend it because it prevents anyone calling them and complaining that their house is cold.  We do not have back-up heat and have never had a problem.  

Steve

On Thu, Apr 14, 2022 at 9:40 PM <seattle-home-e...@googlegroups.com> wrote:

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• Help deciding on a heat pump system - 2 Updates

Help deciding on a heat pump system

"Mike O'Brien" <mobse...@gmail.com>: Apr 14 05:24PM -0700 Hello heat pump fans!   My mother-in-law's gas furnace died this week (100 year old single family home in Fremont) and I have two bids for heat pump replacements and each bid has a ducted heat pump option and a ductless/mini-split option.   The house is one story with a partially finished basement, and has about 1000sf on the living floor with two bedrooms, one bath and kitchen, living room and dining room.   The two contractors are Energy Works out of Montlake Terrace and Resicon out of Tacoma. Both seemed knowledgeable and professional. Energy Works would be installing Daikin equipment, Rescion is installing Mitsubishi equipment. Neither of the estimators took any measurements in the house, let alone did any tests or calculations on how tight the house is or how insulated it is, so I am a little concerned that everything is oversized. (The house is typical 100 year old, not very tight and not very insulated, so maybe their assumptions are safe.)   Here are some spec breakdowns:   Manufacturer Duct? Heat Size HSPF SEER Indoor Sizes (BTU) Backup Heat? Total Price (inc tax) Daikin Ductless 24,000 BTU 12.7 18 18k, 9k, 9k BTU no $15,776 Daikin Ducted 22,800 BTU 10 18 N/A 5kw $16,258 Mitsubishi Ductless 28,600 BTU 11 18 14k, 9k, 6k BTU no $15,206 Mitsubishi Ducted 26,000 BTU 10.4 19 N/A no $17,366   I am interested in thoughts on:   1. Energy Works vs Rescion? Any concerns with either. Strong feelings I should try anyone else? (I also tried Evergreen Heating and they said it would be September before they could come out to visit the site.) 2. Thoughts on Mitsubishi vs. Daikin? 3. Thoughts on a ducted system vs ductless? 4. Should I care about having a back up heat source? 5. Anything else you want to share.   Thanks for your input.   Mike   -- **************************** Mike O'Brien MOBse...@gmail.com   If you are needing to prioritize other things, including self-care, please do not feel obligated to respond immediately.

"Jonlin, Duane" <Duane....@seattle.gov>: Apr 15 04:12AM Hi MIke! You didn't tell us how many interior heads you'd have for the ductless, or whether the configuration looks like it is capable of keeping all the occupied areas of the house comfortable with open or closed doors. Would the ductless arrangement allow you to have different temperature settings in the different zones? DJ     [https://outlook.office365.com/owa/service.svc/s/GetFileAttachment?id=AAMkAGY3MDY0NjRkLTVhMTktNDUxYi04ODRlLTJmOGUwZmZlZDYwOABGAAAAAAC%2BIIpBtcdlQLH6GxS%2B8kZXBwBHxbfB%2FelIQIdaMjJ7UONBAAJS4CmEAACT5QLXjoVSRKSJSX43PAK3AATSZV7FAAABEgAQABnQl0jEgZNOoaTHZHjii08%3D&X-OWA-CANARY=Ntd5IvHNvUiuxxFqt3UjB7C4rbDoGtMYOqpUyTl03aVtHkj5sdaYfdU_Qhb1OulVPkCTVrGglbA.]   Duane Jonlin, FAIA Energy Code and Energy Conservation Advisor City of Seattle Department of Construction and Inspections<http://www.seattle.gov/sdci/> P.O. Box 34019, Seattle, WA 98124-4019 P: 206.233.2781 | duane....@seattle.gov<mailto:your%20n...@seattle.gov> [small facebook]<https://www.facebook.com/seattledci>[small twitter bird]<https://twitter.com/seattledci>[small wordpress logo]<http://buildingconnections.seattle.gov/>   As stewards and regulators of land and buildings, we preserve and enhance the equity, livability, safety and health in our communities.   ________________________________ From: seattle-home-e...@googlegroups.com <seattle-home-e...@googlegroups.com> on behalf of Mike O'Brien <mobse...@gmail.com> Sent: Thursday, April 14, 2022 5:24 PM To: Seattle Home Electrification <seattle-home-e...@googlegroups.com> Subject: Help deciding on a heat pump system   CAUTION: External Email Hello heat pump fans!   My mother-in-law's gas furnace died this week (100 year old single family home in Fremont) and I have two bids for heat pump replacements and each bid has a ducted heat pump option and a ductless/mini-split option.   The house is one story with a partially finished basement, and has about 1000sf on the living floor with two bedrooms, one bath and kitchen, living room and dining room.   The two contractors are Energy Works out of Montlake Terrace and Resicon out of Tacoma. Both seemed knowledgeable and professional. Energy Works would be installing Daikin equipment, Rescion is installing Mitsubishi equipment. Neither of the estimators took any measurements in the house, let alone did any tests or calculations on how tight the house is or how insulated it is, so I am a little concerned that everything is oversized. (The house is typical 100 year old, not very tight and not very insulated, so maybe their assumptions are safe.)   Here are some spec breakdowns:   Manufacturer Duct? Heat Size HSPF SEER Indoor Sizes (BTU) Backup Heat? Total Price (inc tax) Daikin Ductless 24,000 BTU 12.7 18 18k, 9k, 9k BTU no $15,776 Daikin Ducted 22,800 BTU 10 18 N/A 5kw $16,258 Mitsubishi Ductless 28,600 BTU 11 18 14k, 9k, 6k BTU no $15,206 Mitsubishi Ducted 26,000 BTU 10.4 19 N/A no $17,366   I am interested in thoughts on:   1. Energy Works vs Rescion? Any concerns with either. Strong feelings I should try anyone else? (I also tried Evergreen Heating and they said it would be September before they could come out to visit the site.) 2. Thoughts on Mitsubishi vs. Daikin? 3. Thoughts on a ducted system vs ductless? 4. Should I care about having a back up heat source? 5. Anything else you want to share.   Thanks for your input.   Mike   -- **************************** Mike O'Brien MOBse...@gmail.com<mailto:MOBse...@gmail.com>   If you are needing to prioritize other things, including self-care, please do not feel obligated to respond immediately.       -- You received this message because you are subscribed to the Google Groups "Western Washington Home Electrification" group. To unsubscribe from this group and stop receiving emails from it, send an email to seattle-home-electri...@googlegroups.com<mailto:seattle-home-electri...@googlegroups.com>. To view this discussion on the web visit https://groups.google.com/d/msgid/seattle-home-electrification/CAF9WJiT-JHaGwRXF-ZZnuBk3XA3fs-2mHDu%3Dwgmikma8NO1eqw%40mail.gmail.com<https://protect2.fireeye.com/v1/url?k=31323334-50bba2bf-31321b84-4544474f5631-0ca02e0010bf0d1b&q=1&e=59c0386f-8b46-4bae-90c6-1c24ee55f187&u=https%3A%2F%2Fgroups.google.com%2Fd%2Fmsgid%2Fseattle-home-electrification%2FCAF9WJiT-JHaGwRXF-ZZnuBk3XA3fs-2mHDu%253Dwgmikma8NO1eqw%2540mail.gmail.com%3Futm_medium%3Demail%26utm_source%3Dfooter>.

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Steve Gelb
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[Tom Balderston]

Noisy ducts is related to high velocity,  and  also  resistance in the last few fittings and the register.   Inverter heat pumps have multiple speeds,  so i would guess it would only be a problem  when it was pretty cold and the system goes to the highest speeds.     Keep in mind that there is a lot of bad duct design out there...  too many bends,  too much flex duct,  too many 90 degree turns.    Air doesn't  know to turn left or right,  it wants to flow smoothly around curves.   fittings can be changed from 90  takeoffs to  wyes, etc.   

If the ducts are too small,  the air will go faster,   so some runs may need to be increased from 6" to 8"

another source of noise could be not having vibration isolators on the main unit,  but  new heat pumps are probably pretty quiet,  so this isn't as much of an issue with them. 

The best solution is to get rid of the ducts,  and use ductless or even ducted mini split heads,  which can sit in a lowered ceiling  or attic and serve 3 or 4 rooms that are close together.    Ducts are often in crawl spaces or other un heated areas,  and even if they are well sealed  still lose some of the heat before it gets to the room. 

tom