Natural gas?

[ponytug]

Depending on the brand and type of system (ductless vs ducted) you could get 100% heating capacity easily down to 20F outside air temp. System I'm installing in the new remodeled house won't lose any capacity until 20F OAT, and that's because it's a smaller coil than I should use with the outdoor unit I'm using due to price point.

There are ducted lines out there that can easily give you 100% heating down to 5F outside air temp and ductless lines that can give you over 100% heating at -15F outside air temps.

Heat pumps made in the 1990's are not the same heat pumps made today.

I know about the heat pump's fall off in capacity with the outside temperature, and how dependent that is on manufacturer and refrigerant, but I son's think I fully follow your comment above. Can you explain how the (smaller?) coil size affects the heat pump's heating capacity? (Is it that the pump could put out more at a higher outside temp, but is limited by a smaller coil inside, and that only catches up at 20F?) What is the net COP of the system that you are putting in at a temperature, w.g. 20F?

All the best, Peter

 

[Sigarms]

Mitsubishi claims 100% down to -115°F, but only "guarantees" heat down to -22°F.

You're talking ductless, not to be confused with ducted.

Then you have the FX and GXNLHZ that both go down to -22F, but the FX will give you a higher heating capacity @ said 22F

However, the WX model only has a rating down to 17F OAT.

Thus you will find different price points on the WX, HX, GX, GX high heat and FX single zone models (multi zone models will produce less heat per zone vs a single zone system).

 

[Sigarms]

I know about the heat pump's fall off in capacity with the outside temperature, and how dependent that is on manufacturer and refrigerant, but I son's think I fully follow your comment above. Can you explain how the (smaller?) coil size affects the heat pump's heating capacity? (Is it that the pump could put out more at a higher outside temp, but is limited by a smaller coil inside, and that only catches up at 20F?) What is the net COP of the system that you are putting in at a temperature, w.g. 20F?

All the best, Peter

I'm not certain what you mean by smaller coil size?

I'd need to dig into the technical engineering manual for COP at what outdoor designed outdoor temps (other than what a standard submittal will give you at 95F for cooling or 47F for heating), but you're talking coil size and what really helps is having a inverter compressor for ducted systems (it's a given for ductless).

Issue is AHRI isn't catching up to inverter technology per their ratings. Currently, AHRI only rates at 100%. The issue is a single stage compressor runs at 100%, but a inverter compressor does not.

This is why the HVAC industry as a whole is slowly going to inverter compressors.

However, also keep in mind if you put a 20 SEER2 ducted system into 30 year old ductwork, there is a good chance you will only get 16 SEER2 if you're lucky. Please note, it's now SEER2 rating now at a .50 static instead of the old SEER rating of a .30 static that never exists in most duct systems you find.

 

[DarkBlack]

My industrial experience with air sourced heat pumps, was really disappointing on cold NH days, and I’m talking about ones made after 2010. Below 20F, you better be prepared for your 70f temperature to drop to 65f. At 5F, you better have some large supplemental resistance heating elements in it. Below 5F, your going to need an additional heating source if you want to maintain 70f.

This was all with appropriately sized systems.
If you want to maintain 70f, with prolonged temperatures below 20F, then you have to really oversize the heat pump system.

To clarify an often touted heat pump statistic…
The COP, aka 100% heat efficiency @ 20F (for example) some are stating here… That doesn’t mean the system puts out 100% of its heating capacity, as many wrongly believe… it means it gives the amount of heat = electricity used. That’s it.
1w electricity gives 1w heat.

So look at the electric consumption number. If you think on a 5F day, you could keep your house toasty, with just that wattage, then you’re in the minority. Most , at least around here, need much greater than 100% efficiency to maintain temperature

 

[Sigarms]

To clarify an often touted heat pump statistic…
The COP, aka 100% heat efficiency @ 20F (for example) some are stating here… That doesn’t mean the system puts out 100% of its heating capacity, as many wrongly believe… it means it gives the amount of heat = electricity used. That’s it.
1w electricity gives 1w heat.

Not trying to argue.

This picture was taken in 2023

This model has been discontinued since it used R410A refrigerant, but looking at the engineering manual today, with a dry bulb outdoor temp of -5F with a indoor temp dry bulb temp of 70F, the table shows it it will produce 12,600 BTU/h of heat (and this isn't even a high heat unit).

Below is the fan speed table for this unit

Keep in mind, no matter what the outdoor temp, it won't affect the indoor blower speed.

What I can tell you is that for this system in heating, this room (I'd need to go back to my manual J for the exact measurements, but it was done correctly) can maintain a 68F indoor temp at a 5F OAT all day long.

Older heat pump systems used to produce a discharge temp of around 96F, which is why a lot of people didn't like them. Although in cooler temps the room could be kept at 70F indoor, to people used to gas heat (much higher discharge air air temp) a heat pump felt cold if they could feel the air blowing on them because the discharge air temp was lower than their body temp.

I'm a big proponent of experimenting on my own home for "real life conditions" and what I can tell you is that you can use some standard ducted heat pumps and maintain 70F inside at 10F outside air temp all day long, even in New Hampshire (and a single stage will bring on your strip heater faster than a two stage compressor at the same outdoor temp).

I was never a big proponent of whole home dehumidifiers because the argument was that a variable speed blower with a multi stage compressor can dehumidify better that a standard blower with single stage compressor, and that is true, but it can never come as close as dehumidifying better with a single stage compressor with standard blower HVAC system using a whole house dehumidifier.

Don't get me wrong, I would still use a furnace for back up heat if I lived up north, but I would still dual fuel it with a heat pump if I we're on LP for fuel because pretty much any single stage heat pump will handle down to 30F OAT without strips, and in most cases generally cheaper to run electric than burn propane (at least in my area where it's over $3.50 a gallon. For the price difference on a heat pump outdoor unit vs AC outdoor unit (using pretty much the same coil) the ROI can be had in the first year on high dollar LP using gas as a secondary heat.

 

[DarkBlack]

Not trying to argue.

This picture was taken in 2023

View attachment 5039141

This model has been discontinued since it used R410A refrigerant, but looking at the engineering manual today, with a dry bulb outdoor temp of -5F with a indoor temp dry bulb temp of 70F, the table shows it it will produce 12,600 BTU/h of heat (and this isn't even a high heat unit).

Below is the fan speed table for this unit

View attachment 5039767
Keep in mind, no matter what the outdoor temp, it won't affect the indoor blower speed.

What I can tell you is that for this system in heating, this room (I'd need to go back to my manual J for the exact measurements, but it was done correctly) can maintain a 68F indoor temp at a 5F OAT all day long.

Older heat pump systems used to produce a discharge temp of around 96F, which is why a lot of people didn't like them. Although in cooler temps the room could be kept at 70F indoor, to people used to gas heat (much higher discharge air air temp) a heat pump felt cold if they could feel the air blowing on them because the discharge air temp was lower than their body temp.

I'm a big proponent of experimenting on my own home for "real life conditions" and what I can tell you is that you can use some standard ducted heat pumps and maintain 70F inside at 10F outside air temp all day long, even in New Hampshire (and a single stage will bring on your strip heater faster than a two stage compressor at the same outdoor temp).

I was never a big proponent of whole home dehumidifiers because the argument was that a variable speed blower with a multi stage compressor can dehumidify better that a standard blower with single stage compressor, and that is true, but it can never come as close as dehumidifying better with a single stage compressor with standard blower HVAC system using a whole house dehumidifier.

Don't get me wrong, I would still use a furnace for back up heat if I lived up north, but I would still dual fuel it with a heat pump if I we're on LP for fuel because pretty much any single stage heat pump will handle down to 30F OAT without strips, and in most cases generally cheaper to run electric than burn propane (at least in my area where it's over $3.50 a gallon. For the price difference on a heat pump outdoor unit vs AC outdoor unit (using pretty much the same coil) the ROI can be had in the first year on high dollar LP using gas as a secondary heat.

I don’t want to argue either, other than standing by my previous statements regarding my own real experience in an industrial environment, combined with the fact that they aren’t very popular in NH for a reason..

Surely you’re not suggesting the manufacturer’s temperature of 100% efficiency is misleading?
That number is the undeniable science. A heat pump that uses 5kw of electricity, is at best, putting 5kw of heat into your interior ar that temperature. Better hope you like heating with electricity on cold days. Operating a heat pump at 100% is a terrible way to heat your interior.

Then there’s the reliability issue with heat pumps… That’s another whole subject. Let’s just say, HVAC people make a living on heat pumps

 

[Sigarms]

I don’t want to argue either, other than standing by my previous statements regarding my own real experience in an industrial environment, combined with the fact that they aren’t very popular in NH for a reason..

Surely you’re not suggesting the manufacturer’s temperature of 100% efficiency is misleading?
That number is the undeniable science. A heat pump that uses 5kw of electricity, is at best, putting 5kw of heat into your interior ar that temperature. Better hope you like heating with electricity on cold days. Operating a heat pump at 100% is a terrible way to heat your interior.

Then there’s the reliability issue with heat pumps… That’s another whole subject. Let’s just say, HVAC people make a living on heat pumps

I'm just wondering how that new addition room (3 exterior walls) can maintain 70F inside temp at a 5F outside air temp from the pic I posted of 122F discharge air temperature when you stated it shouldn't be able to maintain that temperature?

On a side note, percentage wise vs market share, there probably isn't much difference in a warranty ratio between AC / Gas systems or heat pump systems. The biggest issue facing the industry is familiarity and training. Up north, package units (heat pumps or gas electrtic) go on top of buildings. Down south, the can either go on the roof or on the ground LOL

 

[Larry Caldwell]

Here is one that would help in case of power outage!

View attachment 5017879 View attachment 5017880


Cheers

I have one. I have never used it. I used a stove top toaster years ago when I was camping, but that was more trouble than it was worth.

 

[Larry Caldwell]

There are "cold climate heat pumps" that put out the rated heat amount down to -20°F. We installed a total of 4 units and I can anecdotally confirm that.

Mitsubishi claims 100% down to -115°F, but only "guarantees" heat down to -22°F.

The issue is efficiency, not capability. Heat pump efficiency takes a big hit when it starts de-icing the coils.

 

[Carl_NH]

I agree with you sigarms - we have 4 Mini split systems all single zone high seer Mitsubishi units.

My office in detached garage is 800 SF, cathedral ceilings R38 roof, r21 walls with a 9K Mitsubishi MSZ-FH09A 30.5 SEER, and 4.0 COPF at 47 degrees, and a COPF of 2.73 at 5 degrees. (1 W in = 2.73 watts heat out)

Yes, it works hard when its 0 to 5 OAT to get above 62 degrees inside, but it works fine - most of the time we are 15-20 as the low here.

As far as consumption, I used to heat with a Monitor Kerosene heater, and would go through 200 gal a winter at 3.50$ a gal. Now my electric bill is $400-500 for the winter months (attributed to heating).

Our other Mini split are for "conditioning and supplemental heat and we use oil for the primary in the house.

 

[Sigarms]

Talking about dual fuel, just got this on my phone tonight LOL

I guarantee you they don't make the outdoor heat pump though.

 

[DarkBlack]

9K Mitsubishi MSZ-FH09A 30.5 SEER, and 4.0 COPF at 47 degrees, and a COPF of 2.73 at 5 degrees. (1 W in = 2.73 watts heat out)

I’m looking at the specs on that unit, and it’s showing 100% efficiency (expensive electric heater), at 10F , which seems about right.
How are you coming up with 273% efficient @ 5F ? Maybe you mean 5C

 

[Sigarms]

My office in detached garage is 800 SF, cathedral ceilings R38 roof, r21 walls with a 9K Mitsubishi MSZ-FH09A 30.5 SEER, and 4.0 COPF at 47 degrees, and a COPF of 2.73 at 5 degrees. (1 W in = 2.73 watts heat out)

That's the OLD hyperheat model like 3 generations ago.

You aren't paying for the SEER rating on that model, but the heating capacity it can produce.

Do you use your iSee sensor function at all under the wall mount? That use to drive some people bat crap crazy because some people could hear it rotating when they had the fan speed set to low.

 

[Sigarms]

I’m looking at the specs on that unit, and it’s showing 100% efficiency (expensive electric heater), at 10F , which seems about right.
How are you coming up with 273% efficient @ 5F ?

I've got to ask, where are you pulling your information from when you state "it's showing 100% efficiency at 10F"?

I'm seeing

7,630 BTU/h heat @ -13F OAT
9,260 BTU/h heat @ -4F OAT
10,900 BTU/h heat @ 5F OAT
12,200 BTU/h heat @ 17F OAT

No where do I see 100% efficiency.

My COP's are slightly different than Carl's, but I'm looking at the MSZ-FH09NA and MUZ-FH09NA model 2.37 COP @ 5F OAT

 

[DarkBlack]

I've got to ask, where are you pulling your information from when you state "it's showing 100% efficiency at 10F"?

I'm seeing

7,630 BTU/h heat @ -13F OAT
9,260 BTU/h heat @ -4F OAT
10,900 BTU/h heat @ 5F OAT
12,200 BTU/h heat @ 17F OAT

No where do I see 100% efficiency.

My COP's are slightly different than Carl's, but I'm looking at the MSZ-FH09NA and MUZ-FH09NA model 2.37 COP @ 5F OAT

 

[Sigarms]

View attachment 5045675

That 100% heating capacity, NOT 100% efficiency.

The issue with efficiency is how AHRI rates a inverter compressor (which I mentioned in post #203) which has been going on since day one when mini splits first came into the US market over 40 years ago.

Below is the AHRI certificate for a new FX09 "Hyperheat" system

Honestly, I've given up on exactly what our leadership is trying to do when it comes to efficiency and HVAC systems. What I do live off of is engineering manuals to give me the actual data I need to determine the best system to meet the requirements along with price point options (I don't know anyone in NC who does a load design for heating over a 23F OAT).

The above system will give you 14,500 BTU/h of heat at -5F outside air temp. However, the issue is when that inverter compressor is working over 100% to achieve maximum output, it's very less efficient.

Honestly, you want the best system to go with IMO, go geothermal, the issue is the up front costs because you still have the same ductwork to deal with. If I was still living up north and I wanted the best heating, nothing beats water for heating for comfort IMO, but that's if you're actually able to do it.

Keep in mind, per this thread, I'm finally going to natural gas with a heat pump for primary cooling and heating, but using gas whenever I want for heat (no different than my current home on the second floor where we sleep at night), the issue there is I've been on LP for the last 20 years. My wife doesn't really care about the HVAC and trusts me to take care of it, however, she does want a gas stove and I consider it a win win because I can tell the LP company to jump off a cliff now LOL

That said, pray for me. Have to meet the engineer from our new power company conglomerate to run underground electrical to the house. We read their 5 page document we had to sign, and I was freaking out enough to call the electrician at the new house to explain it to me LOL. Perhaps the new electric company will be just like the old LP company, time will tell...

 

[Carl_NH]

That's the OLD hyperheat model like 3 generations ago.

You aren't paying for the SEER rating on that model, but the heating capacity it can produce.

Do you use your iSee sensor function at all under the wall mount? That use to drive some people bat crap crazy because some people could hear it rotating when they had the fan speed set to low.

Yes -- installed in 2015-16 it was the best unit at that time for efficiency. Yes, it has the iSee sensor as all of ours do - I don't pay any attention to it.

I let mine run all the time now - I used to turn off on weekends then back on during the week when I am in the office but stopped doing that 2 years ago as they like constant running inverters and aren't "fast heat".

As far as the COP as I understand a 2.xx or a 4.xx factor is the heat out per watt in so if you input 1 watt you get 2.xx equivalent watts of heat output.

There is no argument, the colder it gets the less efficient they are, and below 5 OAT is not the sweet spot for mini splits..

 

[Sigarms]

Yes -- installed in 2015-16 it was the best unit at that time for efficiency. Yes, it has the iSee sensor as all of ours do - I don't pay any attention to it.

I let mine run all the time now - I used to turn off on weekends then back on during the week when I am in the office but stopped doing that 2 years ago as they like constant running inverters and aren't "fast heat".

As far as the COP as I understand a 2.xx or a 4.xx factor is the heat out per watt in so if you input 1 watt you get 2.xx equivalent watts of heat output.

There is no argument, the colder it gets the less efficient they are, and below 5 OAT is not the sweet spot for mini splits..

Ironically the issue I've come across with the iSee sense was with elderly people who run the fan on low continuously, and their hearing is better than mine LOL

One thing I don't like about Mitsubishi on those systems is the remote control is not very intuitive IMO (at least the old ones).

That said, I generally use another manufacturer over years now, so I don't keep up to date with everything that they're upgrading to per controls. That said, nothing about quality, but more along with personal preference from my own experience.

I'm a huge fan of ductless, but ironically enough, I'm not a huge fan of using a single multi zone system with more than 2 indoor heads per system. People also think it's cheaper to use a multi zone system vs a single zone, and it isn't except if your paying for electrical for outdoor unit hook up.

Thing is, more and more ducted manufactures (Carrier, Trane, Lennox, Goodman and everyone one else) is slowly going to a inverter compressor horizontal side discharge outdoor unit using a ducted air handler for conventional ductwork. In another 20 years, I doubt anyone will be using a single stage compressor anymore.

Oh, and you 100% right IMO about just letting the system run. I'm getting too old for this industry because everyone wants something to control their system on their phone. For vacation homes where you spend little time at I can see just lowering the temps on the system, but playing "on off" on your phone with a new HVAC system only hurts it more over the years. Added, the biggest PITA issues I've seen is in remote areas where the wi fi isn't the greatest, and the issue isn't the system, but the wi fi.

 

[riptides]

...Getting back to gas for a second, that boom that leveled a house a week or so ago... multiple companies are still looking for the leak as of this AM. The neighborhood is evacuated around the explosion, 50 homes, and they are thinking to expand the area of evacuation.

...back to the Heat Pump engineering and specs information.

 

[Sigarms]

Staying on the new theme...

When 32 and 454 came out, this was the theme with many guys.

Thing is, most videos came from third world countries.