Heating my hot water--four options

[Nate]

Hi- We just moved into our new 1940 era house. There is inadequate hot water for our needs. We live in the northeast and have an oil fired furnace with a steam heating system, radiators. The furnace is a Peerless, circa 1977. Running through this boiler is a tankless coil for 'instant' hot water. Everything works fine except the tankless coil doesn't produce hot water fast enough to give a bath to my kids.

So here are my options, as I see them. . . I don't mind paying more up front if it means fuel savings down the road.

1. Irving (my oil supplier) wants to put in a 40 gallon indirect hot water heater that would essentially be a new zone from my furnace . . 00, installed.

1. My local plumber also suggested putting in an indirect heated 40 gallon hot water tank but suggested we use the existing coil running thorough the boiler to heat the water. ... 00 installed.

2. My friend, who is a plumber who lives in another state who I saw at a conference this weekend suggested a sperate oil fired hot water heater . . cost ????.

1. I was considering putting in a regular gas fired (like from home depot) hot water heater myself. (we have a city natural gas line). And I was also considering running the water through the coil in the boiler to preheat it in the winter when the boiler's running anyway (not sure if that would save money or not).

Any advice greatly appreciated. Many thanks. -Nate Greene

[barry]

Hi, Nate.

Climate varies greatly across the NE, with varying degree and intensity of summer. During which you (well, at least I) would not want to be running a steam-boiler, for a bunch of reasons. That makes the separate water-heater preferable.

Which one, which fuel, would depend on factors invisible from here. An oil-burner is going to cost much more than a gas-burner, and require regular service. Your expertise with water and gas piping are a matter for you and your building inspector, not to mention SO, and her valuation of safety/peace-of-mind.

As an aside, it would seem that in winter, with a steam-boiler, an "economizer" (heat-exchanger in the stack) with a loop to the hw storage tank & a circ-pump that runs with the oil-burner, would be a Good Thing.

HTH, John

[scott_z500]

1. Get rid of kids.
2. Insulate hot water lines. You'd be amazed at how much a difference this can make.
3. Regular gas water heater.

[John Harlow]

Why does hot water need to be heated?

[m Ransley]

Your boiler is probably no more than 70% efficient even if it has been maintained, the hot water loop in winter is therefore 70% and a drag on the boiler, In summer it is less than 70% because it is a secondary heat so maybe it is 50% efficient and heating the house a bit. When AC is on.

1300 for a new gas tank? That is high for a regular cheap water heater. Consider 2 things, block off boiler coil and a Tankless Takagi Flash TH

-1 is the newest Takagi model out with a Ng efficiency of 92%, 95% on propane, and will meet a 3 shower house needs. You will save on standby loss 10-20% , and never run out of hot water. I have a Bosch-Takagi Tankless and wont go back to tank. My summer gas bill is 6-8$ , I took out an electric tank and electric went down 25-30$. And my unit is only

82% efficient. There are a few gas tankless units out from 82-87% Rinnai is good also, but 92-95% is the new Takagi TH-1 Takagi makes Bosches large units of 83% efficiency and are sold at HD and Menards, tankless will save you the most money in utilities.

[Joe S]

To make it hotter.

Was this a trick question??????

Joe

[John_B]

I lived in an 1850s house with an oil fired steam heating system and a water heating coil in the boiler for seventeen years. During the heating season the domestic hot water got TOO hot because it was inside boiling water. During the rest of the year the aquastat which heated the boiler feed water to heat the domestic water maintained a sensible temperature.

Questions: Is the coil clogged? Is there some crud inside the coil which is reducing the rate of heat transfer so it does not heat water fast enough? Is the aquastat [which controls the boiler feed water temperature when the thermostat is not telling the oil burner to make steam to heat the house] set at the proper temperature?

[Nate]

Thank you everyone so much for the information. Sounds like a seperate gas heater is the way to go. I'll have a pro do the gas line.

Bob- If I do a preheat through my boiler. would I remove the mixing valve from the current tankless coil and just do a straight shot through the tankless coil then into my new hot water heater, or would I leave the mixing valve for safety.

Also anyone know the pros and cons of tankless versus tank gas hot water heaters?

Thanks again. I am really grateful for the response. -Nate Greene

Marilyn & Bob wrote:

[Nate]

About face.

I just called my gas company. Although I have a gas line into my house, it has been 'retired'. I was assuming it just needed to be turned on, but I was wrong. They want about $2000 to run a new line into the house. But if I convert my furnace to natural gas, they'll do it for free. Any opinions?

[Beachcomber]

Both oil and natural gas prices flucuate these days...

But right now, the price of oil is going to the stratosphere.

I would go with option #4 (separate gas)

Beachcomber

[Edwin Pawlowski]

Good in the winter, probably not so good in the summer for efficiencly.

About the same as above.

Better option, IMO.

This is probably the best so far. I'm not sre about hte pre-het though. NG is usually a bit ceaper than oil, much cheaper than electric.

How about a point of use heater for the bathroom? It will satisfy the bath and not detract from existing supplies if the DW is running at the same time.

[m Ransley]

You could get a new 83% gas boiler and save over your old unit,and have cheaper gas to use for cooking and the dryer. Run your numbers before you say no, I pay apx 1$ a therm Ng and 0.12kwh. electric for me is several times more than gas or aps 3$ a therm, compared to Ng 1$ a therm. Is you go all electric for cooking and your dryer and HW, you will be paying many times more then if you convert. A new gas boiler may save you 10-20% and yours is not new at all . I would go new boiler, and tankless Takagi and a free gas line. The Takagi drawback is 2- 3 reduced flow showers at one time I dont find a drawback I like the savings on my bill.

[Marilyn & Bob]

Strongly recommend the gas water heater supplied by the tankless coil. If you (or the local codes) decide not to install it yourself, you'll still do better with a professional install of a gas heater than the other two solutions. And you save lots but not having to fire up your boiler in the non-heating season. If you feed the heater from the tankless coil you will save a lot of gas. Our gas bill tripled during the summer when the boiler (hot water, not steam) was not running. Also since your boiler is almost 30 years old, you might need/want to replace it in the next decade. When you do, you could save a lot by getting a new boiler without a tankless coil (especially if you choose gas heat) and the gas hot water heater would fit right into that setup.

[Doug Miller]

Furnace conversion sounds cheaper than a new gas line...

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[maradcliff]

I think you answered your own question. Do #4. You can buy a gas heater for $150 to $200 (or more). If you do the work yourself, the whole job should cost you $500 tops, and probably less, unless you need lots of pipe or something. Go ahead and use the coil to pre-heat. I did the same thing with a solar pre-heater, and in the hottest part of the summer, the water heater rarely or never ran. It only makes sense, the hotter the water when it goes into the heater, the less the heater works, thus the less fuel you need.

It sounds like your "Irving" is trying to find a sucker to boost their income....

If you do install a gas tank, I'd use a few valves and some pipe and design a direct cold water inlet. In other words, you can turn a few valves and get cold water direct to the tank, *OR* reverse the valves and use the preheater. That way, if you dont want to use the preheater for some reason, you can turn it off.

Mark

[Marilyn & Bob]

It looks like this question may no longer be relevant if you decide to get a new gas boiler without a tankless coil. But if you still need an answer, I'm sure someone else here could supply it. Ours was an oil fired boiler for a hot water (not steam) heating system, so no mixing valve was necessary as the water was at an appropriate faucet temperature when it left the coil.