Question on indirect tank setup without also having a hot water heating system

FloMo201 · April 21

Hi All,

My husband & I bought a vacation home which needs some TLC. The heating is via electric baseboard while domestic hot water is via a 40gal gas fired hot water heater. The hot water heater needs replacing, as it is leaking so we killed the gas and drained it out.

I am intrigued by indirect setups and wanted to know if I can do something like this without changing out to hot water heating. Do they make heat sources on gas small enough to just run an indirect water tank?

TIA, Flo

pecmsg · April 21

Where is this vacation home? Straight Electric heat is really expensive.

On demand water heaters have their good and bad. Water quality plays a big part in the decision. What size also.

EBEBRATT-Ed · April 21

No. Stick with a gas or electric water heater unless you willing to ditch the electric baseboard.

But if it is a vacation home and not occupied all the time electric for heat needs little to no maintenance and can't freeze up.

Electric WH would probably be better for intermittent use but would cost more to run.

mattmia2 · April 21

You can get stainless or plastic electric water heaters from a number of manufacturers if corrosion is your concern. Check that the water chemistry is compatible with the tank, especially water with high chlorides can be tough on stainless or plastic tanks.

FloMo201 · April 21

House is in Vermont, so we would keep heat on in the winter as we want to use it all year. Converting to hot water baseboard is just not in our budget right now. I guess the right answer is to replace the hot water heater with a regular 40gal tank for now. As we renovate, we should consider plumbing for baseboards and make the conversion at that time.

Can we approach this is stages….say do a high efficiency boiler for the parts of the house that we will renovate first, leave the electric heat in other parts of the house and then add on to the boiler later as we do other parts of the house?

ethicalpaul · April 21

Question on indirect tank setup without also having a hot water heating system

FloMo201

Apr 21, 2025

Hi All,
My husband & I bought a vacation home which needs some TLC. The heating is via electric baseboard while domestic hot water is via a 40gal gas fired hot water heater. The hot water heater needs replacing, as it is leaking so we killed the gas and drained it out.
I am intrigued by indirect setups and wanted to know if I can do something like this without changing out to hot water heating. Do they make heat sources on gas small enough to just run an indirect water tank?
TIA, Flo

Your question is very confusing to me I admit. You have gas but instead of buying a new gas water heater, you want to set up some kind of indirect tank? What is your imagined benefit here?

FloMo201 · April 21

@ethicalpaul , I was merely thinking of efficiencies in making hot water. We are going to see how badly the electric bills are from the heating setup. If we convert heating the house to gas fired hot water, I will figure out if an indirect would be worth it at that time.

I think everyone convinced me to just replace the water heater with another standard gas fired unit and move on :)

Thanks, Flo

pecmsg · April 21

when you start to get your electric bills for that electric baseboard, you will reconsider.

consider getting a small gas furnace, but keeping the baseboard as your back up.

Larry Weingarten · April 21

Hi, By gas, do you mean natural gas or propane? Propane is usually much more expensive than natural gas for the delivered energy. Also, has anything been done to look at plumbing or fixture flow rates? This could help with saving energy by making things efficient.

Yours, Larry

FloMo201 · April 21

@Larry Weingarten….natural gas. Interesting, no, we have not looked at flow rates and I doubt the previous homeowner did. I will look into that as well.

Thanks, Flo

Jamie Hall · April 21

FloMo201

Apr 21, 2025

@Larry Weingarten….natural gas. Interesting, no, we have not looked at flow rates and I doubt the previous homeowner did. I will look into that as well.
Thanks, Flo

I doubt that natural gas is a realistic option. Most of Vermont doesn't have it within miles… Having lived in Vermont, although sometime back, your cheapest bet is oil fired tank type hot water, next best is LP fired tank type hot water

hot_rod · April 21

Check your local energy costs LP vs Oil. A small combi boiler on LP gets you DHW and you add hydronic heat as you go, radiant, panel rads, etc.

I suspect LP may be cheaper than electric heat. Unless a heat pump is an option? But check some of the online sites that have history data, EIA for example.

U.S. Energy Information Administration - EIA - Independent Statistics and Analysis

ethicalpaul · April 21

Jamie Hall

Apr 21, 2025

https://forum.heatinghelp.com/discussion/comment/1853160#Comment_1853160
I doubt that natural gas is a realistic option. Most of Vermont doesn't have it within miles… Having lived in Vermont, although sometime back, your cheapest bet is oil fired tank type hot water, next best is LP fired tank type hot water

you forgot the cheapest by far…heat pump water heater.

Flo, as others are indicating, the cost of baseboard electric home heat is massive (unless you live in Canada near a hydro dam) and will dwarf your hot water concerns.

Also an indirect setup is very expensive and should be looked at skeptically.

I think people think it’s a free by product of home heating which is a dramatic misconception

ethicalpaul · April 21

https://forum.heatinghelp.com/discussion/comment/1853161#Comment_1853161

Flo says she has natural gas

FloMo201 · April 21

I am going to double check….I could have sworn it was nat gas….but I am definitely going to self check myself.

EBEBRATT-Ed · April 21

Last I knew Vermont doesn't have much NG. I am trying to think if I worked on any NG burners up their.

kcopp · April 21

Unless the camp is in Chittenden, Frankin or Addison County its LP gas. And it is limited in those areas.

Where you are there only sometime a tankless WH it the way to go. Only make what you use.

They have some pretty good water treatment set ups for tankless WH that protect from scale.

Zilmet makes a nice unit.

ActivFlo

You can get smaller tankless WH…no need to get a 199K btu unit. Unless you need it.

They are available in 160K and Takagi makes one that is 140K

There is no way I would even consider a heat pump WH.

Plus if you are not there much the risk of legionella bacteria is a possibility of growing in the tank… even a gas tank is a possibility.

Ask Mark Eatherton about that….

EdTheHeaterMan · April 22

I might be one of the few folks here that have been involved with just this scenario.

In the 1980s the family business diversified into becoming a distributor for Buderus Boiler and Riello Burner. As a result of this combination of selling boilers and burners to contractors we also sold them to the family fuel dealer that installed new equipment. At the time our summer home in NJ was heated with electric baseboard and used a 50 gallon electric water heater for two bathrooms and an outdoor shower

An addition was planned that included a 120 gallon jacuzzi with 8 water jets and enough room for 2 adults at the same time. The 50 gallon water heater was not going to cut it for filling the 120 gallon tub. So we installed a Buderus oil fired boiler, and a 40 gallon indirect. That setup never ran out of hot water.

Eventually the addition had a third bathroom added and we heated that room with a Buderus towel warmer using a TRV and there was a game room added that we connected three buderus panel radiators to the boiler. But for the first three years that indirect was the only thing the oil fired boiler operated.

Eventually that building was demolished in favor of a much larger duplex to maximize the value of the property That Buderus was about 6 years old by then so it ended up in my own home about 8 miles from the original location and it is still pumping out heat with a combustion efficiency of 84.6%. We are heating two radiant floor zones, two air handlers with duct coils and an indirect.

Jamie Hall · April 22

Several comments. First, oil fired tank type water heaters seem to get overlooked. They are reliable and have astonishingly fast recovery, so a small one, such as a 32 gallon Bock, will be adequate for almost any normal size house and family.

Second, things may have changed. I'm sure they have… but oil is almost certainly cheaper than LP, per BTU.

Third, I heartily agree. Avoid a heat pump water heater like the plague. Unless you have a tame installer who will come out at all hours of the blizzard, they are trouble. You may get lucky and get one which works the way you want it to when you want it to, but…

FloMo201 · April 22

Good morning everyone,

We purchased jus north of Shelburne VT and my husband swears it is nat gas.

Been reading more on electric heat and I'm inclined to say we will indeed me sticker shocked, so hubby and I are reworking renovation plans to include some sort of gas fired heating source, and as suggested leave the electric as a back up.

If he is wrong, and it it propane, should we explore oil as a heating source?

Thank you all for the input and help. Always appreciated, Flo

pecmsg · April 22

Punch in the cost of the fuel and find out

Fuel Comparison Calculator for Home Heating | Coalpail.com

Jamie Hall · April 22

Shelburne? Then you probably do have natural gas. That's one of the few areas of Vermont which does…

In which case do your sums, but I'm going to suggest that you might get away with a combi, if your heating load and domestic hot water loads are comparable, or else a mod/con for the heating load and an on-demand gas fired hot water system.

This is also one of the relatively few situations where the cost of installing the hot water heat can be recovered in a reasonable time frame. You first electric bill running the electric heat should be opened only while sitting down with a stiff drink handy…

ethicalpaul · April 22

I'm glad you guys are allowing Flo to have natural gas in her home that apparently has natural gas. Some day you might even allow heat pump water heaters to heat water for years for pennies per day in all the homes where that is happening!

Jamie Hall · April 22

https://forum.heatinghelp.com/discussion/comment/1853259#Comment_1853259

When a heat pump water heater has a mean time between failures measured in years, I will. When it's measured in weeks, if not days… sorry, no sale. I know of one off-grid resort installation with six of them. When they are working, they're great. But… the resort has to have one engineer whose half time job is keeping them running (the rest of his time is spent keeping the solar array and battery system running, but that's another story).

EBEBRATT-Ed · April 22

From what I see HPWH are not gaining momentum. Too much money to spend on a throw away appliance that no one wants to fix.

Its like a mini split but worse. You install them they run (hopefully) and when they quit you throw them out

It's hard enough to get someone to fix something simple like a standard steam or water boiler or a furnace all they want to do is replace them. Systems that are more complicated like a HPWH, mini split or Mod cons are even more difficult to fix.

ethicalpaul · April 22

When a heat pump water heater has a mean time between failures measured in years, I will. When it's measured in weeks, if not days… sorry, no sale.

Please provide a reference for that MTBF number and also for gas water heaters, thanks! Mine's at 5 years so I don't think it's measured in days unless I'm the luckiest boy in the land

From what I see HPWH are not gaining momentum. Too much money to spend on a throw away appliance that no one wants to fix.

Definitely a bet I'd take! But sorry for hijacking and respect to you both.

Jamie Hall · April 22

I don't have a reference for a MTBF figure to heat pump water heaters. What I do have is the experience of that off-grid resort I mentioned, where at least one of the six heaters will fail (almost always some arcane control problem) in any given week. Which is why there are six, and not just four which could handle the load. Also my personal experience with them in two of the houses we maintain, where we could be certain that one of the other would require the attention of a maintenance guru type (again, control problems) a couple of times a summer.

In the case of the residences, the owners are good with sums and quickly figured out that they were spending more on maintenance than they were saving on energy and reactivated the old oil-fired water heaters. In the case of the resort, they really don't have much of a choice; no fuel available (like… none) and limited electricity, so they grin and bear it and the maintenance guys and gals stay gainfully employed…

hot_rod · April 23

https://forum.heatinghelp.com/discussion/comment/1853279#Comment_1853279

Gosh solar thermal and PV should be pretty hands off these days. A drainback ST with only one moving part and a simple control has little to fail.

We put a large ST array on a YMCA camp in Missouri, rubber pool collectors as it is summer use only. Flip a switch every summer and fall and it provides over 80% of the DHW. It's been running trouble free for at least 10 years.

Your systems must have some archaic controls if they are that problematic.

I don't see a HPWH being much more complex than a refrigerator. With a back up element you should never be without DHW.

The weak link in any tank type water heater, gas, electric, HP seems to be the tank life itself. An electronic anode or one of the stainless tank type would handle a lot of those concerns.

mattmia2 · April 23

or the solar is poorly installed

you are forgetting with the hp water heaters that we somehow as a species forgot how to manufacture copper tubing about 15 years ago.

Kaos · April 24

Also have a stiff drink ready when you receive the quote for the modcon+baseboard retrofit. You'll need something MUCH stronger than when opening the utility bill.

A reasonable cost save is to install one or two wall mount cold climate mini split heat pumps in the main living space that can carry say 60% of your heat load. You still use the resistance baseboard to even out the heat in the place around the perimeter but now your bulk heat would cost about 1/3 less. Bonus, free AC in the summer. This will be significantly cheaper than a hydronic retrofit and much less intrusive.

Your heat load is pretty easy to figure out from your utility bill. Once you have a cold month heating costs, you can do the math here (you'll have to convert your kWh to Therms for the math).

https://www.greenbuildingadvisor.com/article/replacing-a-furnace-or-boiler

Glenn_Venco · April 24

If you have gas and it's a vacation home, why not consider an instantaneous heater? For just the two of you, there will be more water than you could theoretically need, and you'll only pay for fuel when using it. Having any type of tank heater doesn't make sense to me. There is too much standby heat loss and intermittent fuel usage when no one is there.

The wall-hung instantaneous gas heaters are small, don't take up much space. Relatively easy to install, but will be more costly than a tank heater. Two possible concerns - size of the gas line (btuh available) to run the heater, and the quality of the cold water - any sediment will quickly clog up its filter.

kcopp · April 25

Which is what I said…. ^^^

Question on indirect tank setup without also having a hot water heating system

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