Use D.H.W. coil or electric H.W. for hot water

Kevin_71

Thanks all for your comebacks, lots of good info out there! Right now due to the economic situation I'll have to stick with what I have for now. I checked the tag from the last cleaning and tune up, and it claims I'm running at 80% efficiency.

The last time I asked my oil dealer about replacing the boiler (approx. 10-15 years ago) he stated that I wouldn't gain that much more efficiency by going with a new setup, that thew only thing that made the new systems more efficient was that new boilers carry less water...but this was quite a while ago so I suspect they've made more improvements in the efficiencies of oil fired rigs.

FYI it's a how water heating system, with 1 big loop of piping feeding the whole house, it's a small ranch house and the heating system was put in somewhere in the late 60's or early 70's (I can remember the house having a hot air "floor furnace" when growing up!)

Kevin

Kevin_71

Oil fired D.H.W. off boiler coil VS. electric H.W. heater

I've got an old Crane "Sunnyday 11" boiler with a Beckett AF burner with a 1 G.P.H. nozzle, and I presently get all my D.H.W. from the coil on the boiler, with no problems with capacity.

The coil works well enough for me, but I was wondering if it'd be more economical to abandon the coil setup and go with an electric heater for my hot water instead, this would allow me to shut off the boiler completely during the Summer months instead of having to run it all year long just for D.H.W usage...any thoughts on this?

World Plumber

Both

I my area we pipe the water through the coil into the electric water heater. In the winter you feed preheated water into the tank and it will rarely come on in the summer the coil will temper the water some before it enters the tank so you have less degrees to raise the temperature and the boiler doesn't run all summer.

Robert O'Brien

Depends

on oil and electric prices.On LI electricity is 21c KWh and oil is $1.859 COD. 140,000 BTU/gal and 3413 BTU/Kwh.Even accounting for the horrendous efficiency of your current system,oil is less than 1/2 the cost of electricity here.I'd invest the $$ you'd spend on a HWH and invest in an efficient heat/DHW system

joe p_3

dhw coil vs electric

I just saw one yesterday - oil-fired tankless dumping dhw into an electric - no tempering valve. Customer reports ok temp in the summer, very hot during heating season - gee, lemme see...
Do we all agree that kevin should replace a 30-yr old boiler with a modulating gas boiler w/on-demand dhw and spend a lot less on fuel?

Kevin_71

Interesting idea running the boiler coil output into an electric heater...was wondering if this is OK with Mass building/plumbing codes, our local inspector is really a stickler for the code book.

As far as a gas fired boiler goes, I only have L.P. here at the house, there's no pipeline gas in the area, and the last fill up of my tank was quite expensive (thinking of switching suppliers on this...). Right now I only use L.P. for my kitchen stove.

Charlie from wmass

No Joe we do not all agree. the man has oil so saving and getting a new boiler of good quality would be his best bet. Kevin I actually have a tankless feeding my electric water heater. of course it was done this way when I was 8 and oil was expensive here and electric was cheap. I have a mixing vale after the tank and I reciculate back to the coil. I have a welder outlet run from the waterheater breaker as I have not had it wired for many years now. I have the boiler on the replacement list but I find it a point to be able to say my 37 year old boiler is firing 81 % and no leaks. I would not have a customer do this as I would be affraid their system went down when they did not have the option to change it. I have the luxury of being able to change mine out when I want to even look forward to it. My boys could learn a few things watching me and the customer would not complain about kids on the jobsite. So after a very long round about story. Kevin if you want to save money get a competent company to change out your old boiler with a good cast iron boiler and run an indirect heater sized for your usage and get a good return on your investment. BTW is it steam or hot water?