Heating systems for new home - Page 2

BroadHopper · 02-03-2023, 08:11 AM

I know the efficiency of my condensing gas boiler and how much it cost per btu.
I also know the efficiency of my split system and how much it cost per btu.

The efficiency of the mini-split drops as the outside temperature drops. I find the cross-over point. This is where I switch to the more efficient heat.

Also, the gas boiler heats up a cold space rather quickly compared to the split system. So I use gas to increase the temperature and switch to the split.

An engineer told me that a split is inefficient when trying to raise the temperature of a cold home. It is efficient in maintaining a set temperature.

So do some research and use your judgment.

TheProfessor · 02-03-2023, 08:45 AM

I view so many new homes such as this.

With fancy dormers. With window bottoms so close to the roof.

Where do these architects think that the snow and melting snow is going to go?
Under dormer windows.

ishoot308 · 02-02-2023, 06:40 PM

Quote:

Originally Posted by WinnisquamZ

Curious if anyone will be operating their mini spilts for heating this weekend. If so, please let us know how they perform in this weather

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We have used our hyper heat Mitsubishi in a large well insulated “efficiency apartment” over a garage. Last year in -10 degree weather it worked like a champ with no issue. It is the primary source of heat and at first I was skeptical….not anymore!

Will be using again this weekend and I will report back for you.

Dan

ishoot308 · 02-03-2023, 08:37 PM

Quote:

Originally Posted by WinnisquamZ

Curious if anyone will be operating their mini spilts for heating this weekend. If so, please let us know how they perform in this weather

Sent from my iPhone using Winnipesaukee Forum mobile app

As promised here ya go….12 below zero and still keeping up just fine. Approximately 1200 square foot apartment over garage. Mitsubishi hyper heat single zone mini split heat pump, (don’t remember the size). Impressive!

Dan

WinnisquamZ · 02-03-2023, 09:01 PM

Quote:

Originally Posted by ishoot308

As promised here ya go….12 below zero and still keeping up just fine. Approximately 1200 square foot apartment over garage. Mitsubishi hyper heat single zone mini split heat pump, (don’t remember the size). Impressive!

Dan

Same here. Working great

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John Mercier · 02-03-2023, 09:31 PM

Good... that means that with any luck the store will be toasty warm when I get in tomorrow.

Biggd · 02-04-2023, 08:00 AM

Quote:

Originally Posted by ishoot308

As promised here ya go….12 below zero and still keeping up just fine. Approximately 1200 square foot apartment over garage. Mitsubishi hyper heat single zone mini split heat pump, (don’t remember the size). Impressive!

Dan

That's impressive! My house is about 1700 sq ft, lots of windows. With the sun shining in yesterday and the wood stove going full bore it got up to 76. Last night it dropped to 65 with the wood stove going full blast. I set the heat t-stat at 65 in case I didn't wake up to reload the stove.

I've been thinking of adding mini splits for AC and those days, in the high 40's & 50's, when it's not quite cold enough to light the stove.

ishoot308 · 02-04-2023, 08:29 AM

Quote:

Originally Posted by Biggd

That's impressive! My house is about 1700 sq ft, lots of windows. With the sun shining in yesterday and the wood stove going full bore it got up to 76. Last night it dropped to 65 with the wood stove going full blast. I set the heat t-stat at 65 in case I didn't wake up to reload the stove.

I've been thinking of adding mini splits for AC and those days, in the high 40's & 50's, when it's not quite cold enough to light the stove.

I will say that this living space above my garage is only a few years old and is very well insulated and I think that is obviously key.

I have mini splits out at my island camp also but not the hyper heat units just standard ones since I only use them for AC but they also kick butt in cooling down the camp on the hottest of days.

Dan

joec · 02-04-2023, 09:53 AM

I stayed up and monitored my Mitsubishi hyper heat heat pumps until 2AM last night and they performed well above my expectations. The specs on the heat pumps say the minimum temperature to make heat is -13. At 1:30AM, it was -17. The thermostat was set at 73 and maintained at 72 most of the day and dropped to 71, then 70 at 1:30 and stayed there. The house was 70 at 7AM this morning when it was -16.

The heat pump was a one to one 18,000 BTU unit that heated the entire downstairs, stairwell hall, upstairs hall and bath, about 850 square feet.

I have a second 3 head unit for each bedroom and heated only one bedroom last night with that and it did the job.

I have a propane stove in the living room as back up ready to go but it wasn't needed.

I had the dogs out at 1AM and those outside units were really working hard. The efficiency of the heat pumps were probably poor compared to oil or natural gas. The only other thing I noticed was the defrost cycles took a lot longer and it took longer for the heat to ramp back up. That was a little scary when the temperature got down below -14, but the heat pumps passed the test.

DougNH · 02-04-2023, 10:55 AM

Meredith about -17, Mitsubishi hyper heat, 5 heads, 42kBTU (2 years old). Monitored on the kumo cloud app from MA. This is for my 2nd floor, heads in 4 bedrooms and a large 40x20x10 room. Probably not a good comparison as the bedrooms open to a loft/great room and receives heat from the 1st floor which is oil boiler, hydro heat. I usually leave the 1st floor at 58 and 2nd floor at 60 but the heads in the bedrooms do not run much.

The large room (no heat from 1st floor) held 60 all night. As much as I like the system, I would have a backup plan. For us we have a propane wood stove in the large room.

WinnisquamZ · 02-03-2023, 09:25 AM

Called my installer and asked about running my mini split in this cold. I have a 36k btu unit installed with 4 heads. Looking to run only one head. Kids are coming up for the hockey and we need to heat the space we close up for the winter months. I was told the performance will be cut in half, however with only one head running we should have no issues. Turned it on last evening and the space is holding at 62. About 800 sq feet

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ishoot308 · 02-03-2023, 09:36 AM

Quote:

Originally Posted by WinnisquamZ

Called my installer and asked about running my mini split in this cold. I have a 36k btu unit installed with 4 heads. Looking to run only one head. Kids are coming up for the hockey and we need to heat the space we close up for the winter months. I was told the performance will be cut in half, however with only one head running we should have no issues. Turned it on last evening and the space is holding at 62. About 800 sq feet

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Just curious if your split is a hyper heat unit or standard??

Dan

WinnisquamZ · 02-03-2023, 09:40 AM

Hyper heat, I believe. Good for -10 I was told

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WinnisquamZ · 02-03-2023, 09:52 PM

As I have noted in the past. Mini spilts work when left on. Not great at recovery for either heat or ac

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John Mercier · 02-04-2023, 07:31 AM

They held the temperature at the Bristol store...
But the downstairs back up propane-fired heaters are going full bore.

02-03-2023, 08:11 AM	#1
BroadHopper Senior Member Join Date: Oct 2004 Location: Laconia NH Posts: 5,583 Thanks: 3,227 Thanked 1,106 Times in 796 Posts	A liitle math I know the efficiency of my condensing gas boiler and how much it cost per btu. I also know the efficiency of my split system and how much it cost per btu. The efficiency of the mini-split drops as the outside temperature drops. I find the cross-over point. This is where I switch to the more efficient heat. Also, the gas boiler heats up a cold space rather quickly compared to the split system. So I use gas to increase the temperature and switch to the split. An engineer told me that a split is inefficient when trying to raise the temperature of a cold home. It is efficient in maintaining a set temperature. So do some research and use your judgment. __________________ Someday may never be an actual day.

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02-03-2023, 08:45 AM	#2
TheProfessor Senior Member Join Date: Nov 2010 Posts: 1,130 Thanks: 17 Thanked 347 Times in 209 Posts	I view so many new homes such as this. With fancy dormers. With window bottoms so close to the roof. Where do these architects think that the snow and melting snow is going to go? Under dormer windows.

The Following 3 Users Say Thank You to ishoot308 For This Useful Post:
Biggd (02-04-2023), FlyingScot (02-04-2023), Slickcraft (02-04-2023)

The Following User Says Thank You to WinnisquamZ For This Useful Post:
ishoot308 (02-03-2023)

02-03-2023, 09:31 PM	#6
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,426 Thanks: 3 Thanked 600 Times in 496 Posts	Good... that means that with any luck the store will be toasty warm when I get in tomorrow.

02-04-2023, 09:53 AM	#9
joec Junior Member Join Date: Jul 2015 Posts: 13 Thanks: 0 Thanked 9 Times in 5 Posts	I stayed up and monitored my Mitsubishi hyper heat heat pumps until 2AM last night and they performed well above my expectations. The specs on the heat pumps say the minimum temperature to make heat is -13. At 1:30AM, it was -17. The thermostat was set at 73 and maintained at 72 most of the day and dropped to 71, then 70 at 1:30 and stayed there. The house was 70 at 7AM this morning when it was -16. The heat pump was a one to one 18,000 BTU unit that heated the entire downstairs, stairwell hall, upstairs hall and bath, about 850 square feet. I have a second 3 head unit for each bedroom and heated only one bedroom last night with that and it did the job. I have a propane stove in the living room as back up ready to go but it wasn't needed. I had the dogs out at 1AM and those outside units were really working hard. The efficiency of the heat pumps were probably poor compared to oil or natural gas. The only other thing I noticed was the defrost cycles took a lot longer and it took longer for the heat to ramp back up. That was a little scary when the temperature got down below -14, but the heat pumps passed the test.

The Following 3 Users Say Thank You to joec For This Useful Post:
Biggd (02-04-2023), ishoot308 (02-04-2023), Slickcraft (02-04-2023)

02-04-2023, 10:55 AM	#10
DougNH Senior Member Join Date: Aug 2006 Location: Meredith Bay/MA Posts: 79 Thanks: 119 Thanked 49 Times in 19 Posts	Meredith about -17, Mitsubishi hyper heat, 5 heads, 42kBTU (2 years old). Monitored on the kumo cloud app from MA. This is for my 2nd floor, heads in 4 bedrooms and a large 40x20x10 room. Probably not a good comparison as the bedrooms open to a loft/great room and receives heat from the 1st floor which is oil boiler, hydro heat. I usually leave the 1st floor at 58 and 2nd floor at 60 but the heads in the bedrooms do not run much. The large room (no heat from 1st floor) held 60 all night. As much as I like the system, I would have a backup plan. For us we have a propane wood stove in the large room.

02-03-2023, 09:25 AM	#11
WinnisquamZ Senior Member Join Date: Dec 2016 Posts: 2,074 Thanks: 212 Thanked 665 Times in 439 Posts	Called my installer and asked about running my mini split in this cold. I have a 36k btu unit installed with 4 heads. Looking to run only one head. Kids are coming up for the hockey and we need to heat the space we close up for the winter months. I was told the performance will be cut in half, however with only one head running we should have no issues. Turned it on last evening and the space is holding at 62. About 800 sq feet Sent from my iPhone using Winnipesaukee Forum mobile app

02-03-2023, 09:40 AM	#13
WinnisquamZ Senior Member Join Date: Dec 2016 Posts: 2,074 Thanks: 212 Thanked 665 Times in 439 Posts	Hyper heat, I believe. Good for -10 I was told Sent from my iPhone using Winnipesaukee Forum mobile app

02-03-2023, 09:52 PM	#14
WinnisquamZ Senior Member Join Date: Dec 2016 Posts: 2,074 Thanks: 212 Thanked 665 Times in 439 Posts	As I have noted in the past. Mini spilts work when left on. Not great at recovery for either heat or ac Sent from my iPhone using Winnipesaukee Forum mobile app

The Following User Says Thank You to WinnisquamZ For This Useful Post:
FlyingScot (02-04-2023)

02-04-2023, 07:31 AM	#15
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,426 Thanks: 3 Thanked 600 Times in 496 Posts	They held the temperature at the Bristol store... But the downstairs back up propane-fired heaters are going full bore.