Should I convert to gas heat now?

MarkMurf

Being a life long heating service tech I am afraid the longevity of aluminum boilers is in question. If you have one, system water quality and proper chemistry/metallurgy is vital and requires more attention than the average. I have gotten away from using them and have been using stainless steel wall hung boilers instead . With great results .

yesimon

@Stylez777 From your comments it seems like you might have solar or are interested in solar.

One strong possibility for you is heating/cooling mini splits. While heating ROI on mini splits in the northeast is usually pretty bad, you can cross-amortize the operational cost of mini splits with a larger solar panel system which can seriously improve the economics of both. If you are currently using window A/Cs, mini splits have double the efficiency which will save significantly on cooling costs. Finally, they will increase the value of your home if you didn't previously have A/C, although that doesn't translate to cash flow.

bio_guy

I am with those that would do little or nothing with the boiler due to uncertainty with which fuel to choose. OTOH, those gas conversions are so inexpensive, since you are already plumbed for it, installing one of those could easily count as "little".

Doe Penna have an energy efficiency program? Some states did and would pay for (in whole or subsidize) an energy rater to evaluate the structure and HVAC appliances to recommend what gives you the biggest bang for the buck. Do the insulation and air sealing improvements now. When you figure out what fuel and heating appliance you want to go with, you will be able to size it right to the new conditions.

A few of words of caution: I think it difficult to match combination boilers to typical US homes. Another is, what needs to be done with the chimney with a gas conversion gun? I am not saying that the latter will be a problem, but be sure it won't be. Higher efficiency = lower flue temp = more condensation unless the flue is changed.

BennyV

So the big question is, what is your A/C system? If you don't have A/C installed in the house, the obvious solution is mini splits, and put Cryotek or similar in the hot water loops of the oil system to keep it as a backup in case the heat pumps fail or oil is not super expensive and it's sub-20 degrees out for a long time.

The nice part with minisplits is that even in Connecticut, which has legendarily high electricity cost, heating with them is equivalent to around $2/gallon before you factor in the gains from zoning loss, electricity saved not running the oil equipment, and that's all assuming you're running an 87% triple-pass boiler by comparison, which you aren't so your oil efficiency is significantly lower.

Since you have a "legal" or backup heating system, the minisplits only need to be ~80% of design load to heat your house all winter, and in the Northeast, that's more than plenty of A/C as well. The design loads assume Grandma has the heat at 70*, doesn't account for thermal mass to get through the night, and doesn't account for people and electricity usage adding to the heat in the building.

If you already have a functioning A/C system, then the whole equation gets a lot more complicated depending on how it's set up, how old it is, etc, as a lot of A/C systems installed in houses with hot water baseboard primarily cool the upper level, and are of little use for heating a two-story Colonial style house, which even at design loads, needs 90-100% of the cooling upstairs, but 65% of the heating downstairs.

joea99

BennyV said:

. . .
The nice part with minisplits is that even in Connecticut, which has legendarily high electricity cost, heating with them is equivalent to around $2/gallon before you factor in the gains from zoning loss, electricity saved not running the oil equipment, and that's all assuming you're running an 87% triple-pass boiler by comparison, which you aren't so your oil efficiency is significantly lower.

That's interesting. I guess there are differences of opinion on that. I'm in NY and electric is not "cheap" either.

First year I used the mini splits instead of oil, I'm not sure I saved money on heating. I have 4 units, 3 8k and one 12k. Maybe that makes it less efficient overall?

By next winter I will probably try them again and supplement with the wood stove and Fireplace insert. Assuming I don't put off stacking the wood where I can get to it after it snows.

pecmsg

As it gets colder outside the efficiency of heat pumps drop. Around here 20 - 25 degs is the cut off point. 

StephenPelosa

Stylez777 said:

Hi all,

So Currently I have a Thermo-Dynamics S-125 Oil Furnace and a 275 gallon Oil Tank, 40 gal water heater and 3 zone heating system with Hydronic baseboard heat. The Furnace is 84% AUFE and the old owner of the house had it installed probably around 2010-2015, so it not that old.

I had no plans to replace this because 8 months ago, when we moved in oil was $2.50 a gallon and the cost to convert just didn't make sense. Now...oil is near $6 a gallon where Nat Gas is near $2.25 per therm (that is supply and delivery together).

I have gas already in the house feeding my stove and few local plumbers said probably do the convert for what is a market avg price. None of them did any kind of heat loss analysis, just a walk through of the house and look at what I had now. One guy wanted to had circulators for each zone another guy said it better to just leave the 1 circulator pump i already have for all 3 zones.

So the long and short of this is, would it be worth it now, based on current prices and world energy trajectory to do this conversion and if so, what is the best practices or things I should be looking to ask or want when having companies come out to bid/estimate the job?

StephenPelosa

Its just my opinion, but right after Hurricane Sandy, I saved my boiler (which ran on oil) till the spring. During the spring, I switched to Gas. I had a Purefire condensing burner put in. I love it. It's much cheaper for me to run this heating system and much more efficient. Like I said , just my opinion.

BennyV

joea99 said:

That's interesting. I guess there are differences of opinion on that. I'm in NY and electric is not "cheap" either.

First year I used the mini splits instead of oil, I'm not sure I saved money on heating. I have 4 units, 3 8k and one 12k. Maybe that makes it less efficient overall?

By next winter I will probably try them again and supplement with the wood stove and Fireplace insert. Assuming I don't put off stacking the wood where I can get to it after it snows.

How efficient are they? It's only in the past maybe 5 years that they've gotten to a point where they're that efficient. The Mitsubishi multi-split units are around 18-19 SEER and 11HSPF, which is a COP of 3.22. The single-split units have significantly higher efficiencies, but have more limited applications.

pecmsg said:

As it gets colder outside the efficiency of heat pumps drop. Around here 20 - 25 degs is the cut off point. 

So if oil is $2/gallon and you have an 87% triple-pass oil boiler with outdoor reset and ECM pumps, it probably makes sense to switch over in the 15-20F range. However, the Mitsubishi heat pumps have no problem heating well below zero if oil is expensive or you have an old, inefficient oil-fired system. For houses that have electric baseboard, the Mitsubishis with H2i Hyper Heat will still be running at COP of 1.7 at 0F, with 100% output at 5F, so it makes sense to run them as hard as you can. Last time I looked, they cut off at -13F, they may operate a bit colder than that now, but the Carrier Greenspeed has been observed running at -30F. The technology in these things is pretty impressive.

On the other hand, the Unico iSeries tank below about 20F in both efficiency and output, and need hydronic coils from a boiler if you're going to depend on the SDHV for heat. I can't imagine anywhere that SDHV actually makes economic sense, it looks like a huge amount of work to install, it seems more like a luxury option for high-end applications, although I can't really imagine anything more luxurious than a Mitsubishi multi-split high wall cassette in every room, each with it's own thermostat.

pecmsg

BennyV said:

That's interesting. I guess there are differences of opinion on that. I'm in NY and electric is not "cheap" either. First year I used the mini splits instead of oil, I'm not sure I saved money on heating. I have 4 units, 3 8k and one 12k. Maybe that makes it less efficient overall? By next winter I will probably try them again and supplement with the wood stove and Fireplace insert. Assuming I don't put off stacking the wood where I can get to it after it snows.

How efficient are they? It's only in the past maybe 5 years that they've gotten to a point where they're that efficient. The Mitsubishi multi-split units are around 18-19 SEER and 11HSPF, which is a COP of 3.22. The single-split units have significantly higher efficiencies, but have more limited applications.

As it gets colder outside the efficiency of heat pumps drop. Around here 20 - 25 degs is the cut off point. 

So if oil is $2/gallon and you have an 87% triple-pass oil boiler with outdoor reset and ECM pumps, it probably makes sense to switch over in the 15-20F range. However, the Mitsubishi heat pumps have no problem heating well below zero if oil is expensive or you have an old, inefficient oil-fired system. For houses that have electric baseboard, the Mitsubishis with H2i Hyper Heat will still be running at COP of 1.7 at 0F, with 100% output at 5F, so it makes sense to run them as hard as you can. Last time I looked, they cut off at -13F, they may operate a bit colder than that now, but the Carrier Greenspeed has been observed running at -30F. The technology in these things is pretty impressive. On the other hand, the Unico iSeries tank below about 20F in both efficiency and output, and need hydronic coils from a boiler if you're going to depend on the SDHV for heat. I can't imagine anywhere that SDHV actually makes economic sense, it looks like a huge amount of work to install, it seems more like a luxury option for high-end applications, although I can't really imagine anything more luxurious than a Mitsubishi multi-split high wall cassette in every room, each with it's own thermostat.

Yes they’ll heat but it’s a cool heat with defrost cycles increasing. 

I’ll pay a little extra for the comfort. 

ChrisJ

pe sure to eatery back to surecmsg said:

BennyV said:

That's interesting. I guess there are differences of opinion on that. I'm in NY and electric is not "cheap" either. First year I used the mini splits instead of oil, I'm not sure I saved money on heating. I have 4 units, 3 8k and one 12k. Maybe that makes it less efficient overall? By next winter I will probably try them again and supplement with the wood stove and Fireplace insert. Assuming I don't put off stacking the wood where I can get to it after it snows.

How efficient are they? It's only in the past maybe 5 years that they've gotten to a point where they're that efficient. The Mitsubishi multi-split units are around 18-19 SEER and 11HSPF, which is a COP of 3.22. The single-split units have significantly higher efficiencies, but have more limited applications.

As it gets colder outside the efficiency of heat pumps drop. Around here 20 - 25 degs is the cut off point. 

So if oil is $2/gallon and you have an 87% triple-pass oil boiler with outdoor reset and ECM pumps, it probably makes sense to switch over in the 15-20F range. However, the Mitsubishi heat pumps have no problem heating well below zero if oil is expensive or you have an old, inefficient oil-fired system. For houses that have electric baseboard, the Mitsubishis with H2i Hyper Heat will still be running at COP of 1.7 at 0F, with 100% output at 5F, so it makes sense to run them as hard as you can. Last time I looked, they cut off at -13F, they may operate a bit colder than that now, but the Carrier Greenspeed has been observed running at -30F. The technology in these things is pretty impressive. On the other hand, the Unico iSeries tank below about 20F in both efficiency and output, and need hydronic coils from a boiler if you're going to depend on the SDHV for heat. I can't imagine anywhere that SDHV actually makes economic sense, it looks like a huge amount of work to install, it seems more like a luxury option for high-end applications, although I can't really imagine anything more luxurious than a Mitsubishi multi-split high wall cassette in every room, each with it's own thermostat.

Yes they’ll heat but it’s a cool heat with defrost cycles increasing. 

I’ll pay a little extra for the comfort. 

Air to water to air heat pump with buffer tank?

pecmsg

I thought were talking Air to Air!

ChrisJ

pecmsg said:

I thought were talking Air to Air!

I dunno, I'm coming up with ideas here.

BennyV

pecmsg said:

Yes they’ll heat but it’s a cool heat with defrost cycles increasing. 

I’ll pay a little extra for the comfort. 

The Mitsubishi units use the compressor without any fans running to do defrost, so there is no cold air, the Carrier Greenspeed will use aux heat to make up for the heat while defrosting.

ChrisJ said:

Air to water to air heat pump with buffer tank?

We were talking air to air. You lose a lot of efficiency going to air to water to air vs. just straight air to air.

Bronxtech

clean clean it well , make sure the baffles are installed, new gaskets and sealant, spill switch and proper Draft Diverter. Carlin or Riello gas burner and enjoy the conversion for 1/4 of the $$. Make sure they set it up with instruments and clock the meter 👍👍

Lance

Yes convert and don't look back. Saves a lot of ways.

pedmec

Don't wait to long. Don't know if anybody has heard but our friends in the white house are trying to quietly push a bill thru to eliminate the use of gas or oil on new heating installations. I have heard and i don't remember exactly where (i believe California) but they have already banned oil and gas from new installations. They tried it here in the town of Brookline, Ma but the state attorney general shot it down. They wanted to allow only electric heating, from mini split heat pumps. So short sighted. THEY DONT KNOW THEY USE FOSSIL FUELS TO POWER THE POWER PLANTS THAT GENERATE OUR ELECTRICITY. not everybody has hydroelectric.

ChrisJ

pedmec said:

Don't wait to long. Don't know if anybody has heard but our friends in the white house are trying to quietly push a bill thru to eliminate the use of gas or oil on new heating installations. I have heard and i don't remember exactly where (i believe California) but they have already banned oil and gas from new installations. They tried it here in the town of Brookline, Ma but the state attorney general shot it down. They wanted to allow only electric heating, from mini split heat pumps. So short sighted. THEY DONT KNOW THEY USE FOSSIL FUELS TO POWER THE POWER PLANTS THAT GENERATE OUR ELECTRICITY. not everybody has hydroelectric.

Can you share some sources that say this?

"I've heard" doesn't cut it.

pedmec

here's the link to what happened in mass

https://www.bostonglobe.com/2022/02/25/science/brookline-wants-fossil-fuel-free-future-with-latest-ruling-state-says-not-yet-again/

ill try to find the other from cali. it actually might be in this article. i read this article when it first happened. its absolutely nuts. but be aware its an ultra-liberal city. i think they might have been the first with no plastic bags at supermarkets.

plus i don't think its electrical resistance heat they are shooting for. its the success of the mini split heat pumps. i believe that's the road they want to go down

BobRoss

ChrisJ said:

pedmec said:

Don't wait to long. Don't know if anybody has heard but our friends in the white house are trying to quietly push a bill thru to eliminate the use of gas or oil on new heating installations. I have heard and i don't remember exactly where (i believe California) but they have already banned oil and gas from new installations. They tried it here in the town of Brookline, Ma but the state attorney general shot it down. They wanted to allow only electric heating, from mini split heat pumps. So short sighted. THEY DONT KNOW THEY USE FOSSIL FUELS TO POWER THE POWER PLANTS THAT GENERATE OUR ELECTRICITY. not everybody has hydroelectric.

Yes but regulating/monitoring a power plants emissions is fair easier then hundreds of thousands of individual oil burners

Heat pumps have been used for years in montanas winters and they work.

BennyV

It's obvious that the eventual end goal is for everything to be electric. Even with gas combined cycle turbines, heat pumps are way more efficient than burning the gas locally. But economically, the first to convert should be areas without natural gas, as propane and oil are clearly not economical or rational ways to heat a house, whereas gas is a bit more expensive than heat pumps, but not more expensive enough to warrant large scale conversions like oil and propane.

pecmsg

BennyV said:

It's obvious that the eventual end goal is for everything to be electric. Even with gas combined cycle turbines, heat pumps are way more efficient than burning the gas locally. But economically, the first to convert should be areas without natural gas, as propane and oil are clearly not economical or rational ways to heat a house, whereas gas is a bit more expensive than heat pumps, but not more expensive enough to warrant large scale conversions like oil and propane.

And how is the electric made?

Jamie Hall

BennyV said:

It's obvious that the eventual end goal is for everything to be electric. Even with gas combined cycle turbines, heat pumps are way more efficient than burning the gas locally. But economically, the first to convert should be areas without natural gas, as propane and oil are clearly not economical or rational ways to heat a house, whereas gas is a bit more expensive than heat pumps, but not more expensive enough to warrant large scale conversions like oil and propane.

The paradox there is that those areas (where natural gas is not available) also tend to be areas where the electrical grid is least reliable and least able to handle additional load.

Hot_water_fan

 And how is the electric made?

@pecmsg we all know how electricity is made. The point was that heat pumps 100% powered by combined cycle natural gas plants are still more efficient than burning gas on site. It’s not that close either. 

I’ll show the calculations again if I must haha. Using natural gas more efficiently is a good thing!!

ChrisJ

Hot_water_fan said:

 And how is the electric made?

@pecmsg we all know how electricity is made. The point was that heat pumps 100% powered by combined cycle natural gas plants are still more efficient than burning gas on site. It’s not that close either. 

I’ll show the calculations again if I must haha. Using natural gas more efficiently is a good thing!!

Heat pumps using electric generated by natural gas are more efficient than a 95+% efficiency boiler burning natural gas?

Yes please show the calculations again.

Hot_water_fan

@ChrisJ ha it won’t be the last time I’m asked. 

50% efficient combined cycle x 95% (to account for line losses) x 2.5 COP = 1.1875. 20% more efficient than the most efficient gas boiler ever. Obviously the numbers aren’t perfect but they’re reasonable. I put a thumb on the scale for gas by excluding the gas leaks too. You’ll find higher efficiency heat pumps and higher efficiency combined cycle plants (as linked below, the average combined cycle built since 2015 is >50% efficient). Older combined cycles are less efficient, but they’re getting used less and less. I think the math and the trends are pretty clear. Combined heat and power would be even better!

https://evcvaluation.com/declining-natural-gas-fired-heat-rates/

ChrisJ

Hot_water_fan said:

@ChrisJ ha it won’t be the last time I’m asked. 

50% efficient combined cycle x 95% (to account for line losses) x 2.5 COP = 1.1875. 20% more efficient than the most efficient gas boiler ever. Obviously the numbers aren’t perfect but they’re reasonable. I put a thumb on the scale for gas by excluding the gas leaks too. You’ll find higher efficiency heat pumps and higher efficiency combined cycle plants (as linked below, the average combined cycle built since 2015 is >50% efficient). Older combined cycles are less efficient, but they’re getting used less and less. I think the math and the trends are pretty clear. Combined heat and power would be even better!

https://evcvaluation.com/declining-natural-gas-fired-heat-rates/

Obviously this is getting into huge variables but what is the lowest outdoor temperature a typical inverter heat pump can achieve a COP of 2.5?

This isn't a loaded question I literally have no idea.  If they remain fairly high down to 0F then I guess it's a done deal.  But if it drops rapidly below 30F then I'm not so sure for a lot of North America.

Hot_water_fan

Obviously this is getting into huge variables but what is the lowest outdoor temperature a typical inverter heat pump can achieve a COP of 2.5?

Depends on modulation level: the Mitsubishi hyper heats have COP >3 at -13 degrees at 73% load. It’s important to note that even if you hit a low COP at low temperatures, the seasonal efficiency is important to keep in mind, as the low temps are a small portion of the year in North America. No reason these can’t be paired with a furnace for the sub zero temperatures. I think plenty of installations will exceed 2.5 COP, 2.5 was a number I saw from a VT case study. 

Really, it’s the double duty heating/cooling they can perform I think makes it inevitable. Most Americans seem uninterested in efficiency. 

Steamhead

Hot_water_fan said:

.....Really, it’s the double duty heating/cooling they can perform I think makes it inevitable. Most Americans seem uninterested in efficiency. 

The typical duct system is wrong for at least half the year. Plus, most duct systems leak- some rather badly. I'll keep my boiler.

Hot_water_fan

The typical duct system is wrong for at least half the year. Plus, most duct systems leak- some rather badly. I'll keep my boiler.

I understand! The (vast?) majority of American disagree though. 

Steamhead

Hot_water_fan said:

The typical duct system is wrong for at least half the year. Plus, most duct systems leak- some rather badly. I'll keep my boiler.

I understand! The (vast?) majority of American disagree though. 

Many Americans live in development houses with heat pumps, because that's what the builders installed. Consider the business model: Build the houses as cheaply as possible, sell them for as much as you can get, and exit quickly. They wouldn't even insulate walls and ceilings if Code didn't require it.

I once worked with a lady who wanted to have a house built- and a heat pump was the only thing offered. I don't know if she ever actually had it built.

Hot_water_fan

Many Americans live in development houses with heat pumps, because that's what the builders installed. Consider the business model: Build the houses as cheaply as possible, sell them for as much as you can get, and exit quickly. 

Correct! If Americans were willing to pay for boilers, they’d get them. All home builders (well most) intend to make money - if a buyer doesn’t value a boiler, it doesn’t get included. Granite countertops are another story…

Steamhead

I think if offered a choice, more people would go hydronic. But builders refuse to offer that choice.

Hot_water_fan

Become a builder and find out! 

Steamhead

Why would I do that? I like what I'm doing.

Voyager

pecmsg said:

BennyV said:

It's obvious that the eventual end goal is for everything to be electric. Even with gas combined cycle turbines, heat pumps are way more efficient than burning the gas locally. But economically, the first to convert should be areas without natural gas, as propane and oil are clearly not economical or rational ways to heat a house, whereas gas is a bit more expensive than heat pumps, but not more expensive enough to warrant large scale conversions like oil and propane.

And how is the electric made?

https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php

Our biggest mistake is not building more nuclear plants. They are the cleanest and safest way to make electricity on a large scale.

pecmsg

Voyager said:

pecmsg said:

BennyV said:

It's obvious that the eventual end goal is for everything to be electric. Even with gas combined cycle turbines, heat pumps are way more efficient than burning the gas locally. But economically, the first to convert should be areas without natural gas, as propane and oil are clearly not economical or rational ways to heat a house, whereas gas is a bit more expensive than heat pumps, but not more expensive enough to warrant large scale conversions like oil and propane.

And how is the electric made?

https://www.eia.gov/energyexplained/electricity/electricity-in-the-us.php

Our biggest mistake is not building more nuclear plants. They are the cleanest and safest way to make electricity on a large scale.


Nuclear, hydro, solar and wind are only a small part of electric generating. It's going to take much more and a larger grid.

Hot_water_fan

If it’s cleaner using 100% gas and the grid in reality is 40% nuclear + renewables, we’re doing alright!

ChrisJ

@Hot_water_fan How are you heating your hot water that you're a fan of?

Hot_water_fan

@ChrisJ just DHW for me - gas!