Hi folks,
I’m asking for some educated opinions on some domestic hot water options. We’ve decided it’s time to retire our 19 year old domestic hot water heater before it retires itself. Just for further info, there is also a separate boiler for the heating system hot water that’s circulated to baseboard radiators.
The HVAC guy gave us quotes for 3 options:
1) Bradford-White Residential UPDX2-65T6FBN. Basically the same type tank system as what we currently have, but with a powered exhaust fan that he said would reduce the pilot blow-outs that we frequently get here.
2) Dunkirk Indirect Tank connecting to your Boiler already in use. So run everything off that boiler, which is ~16 years old. This about $200 less than option 1.
3) Eternal 195S tankless. $1200 more than option 1. With possibility of expansion by adding a storage tank for increased hot water consumtion, and/or another tank to replace the boiler should that ever become necessary thus running dhw and heating off the 195S. Both these additions at ? cost.
Any opinions or tales of experience with any of these would be most welcome. Thanks much.
Replies
I like #2.
I am not an HVAC pro, but I have considered this often on my own behalf.
I recently saw an instant- on WH on TOH with its own storage tank, which looked like it was about 5 gallons. After reading about tankless for at least a decade, I conclude that this is the only type of instant on water heater I would consider. That is, I consider the shortcomings of the Tankless to be deal killers. There is lots of info on the internet about the pros and cons of this type of setup.
Consumer Reports concluded several years ago that the increased efficiency would need about 10 years to recoup the extra costs of converting to tankless, so it barely breaks even on cost.
I too have a cast iron gas boiler exactly sixteen years old. If I had to replace the current (option #1) HW tank, I would strongly consider option #2. Not only does it cost less, but I suspect that a 240k btu boiler ought to have a real quick refresh rate. (the inbound water gets hot real quick). The next boiler to go in this house (hopefully not soon) will be a high efficiency mod-con, which will now provide really cheap hot water as well when hooked up the existing tank.
I am quite interested to hear the thoughts of others on this subject.
Good luck to the OP.
You should indeed avoid the tankless water heaters as they are not worth it.
Have you considered a heat-pump water heater? If it is in an utility room with the boiler then it could recapture some of the heat lost by the boiler.
How is the refresh time with a heat pump wh?
I wonder how long it takes a heat pump WH to restore the tank to the desired heat? My hunch is that is would be far slower than the other options.
I installed a nautural gas fueled Rianni system 8 years ago. I recouped installation costs in 6 years. There are pluses and minuses to just about every system out there. Anyone that automatically rules out an on-demand water heating system doesn't know (IMO) what they're talking about. My overall take on the issue of tank or tankless: if you have a low hot water demand household with an effeciently installed plumbing layout, you're going to save money and have increased versatility with a tankless unit. I know I have.
BTW, you mentioned an expansion tank for "increased hot water consumption". I'm open to an explanation of how that works, but I don't think it's possible. My understanding is that if you size your unit properly, it will deliver all the hot water you need, whenever you need it. The ability to consume water seems based on your supply line size and water pressure; not the manner in which the water is heated by fuel. Now I have heard about secondary storage tanks being utilized to avoid delays in hot water delivery on long circulation loops; but not to increase capacity. Personally I feel storage tanks are unneccesary (if your on-demand plumbing system supply is laid out properly) and are a waste of energy. After all, the main reason you go with an on-demand heat source is to avoid tanks which are contiually heating (and buying) hot water you're not using.
Heating hot water.
Simply add a indirect hot water cylinder to your central heating boiler. Add a cylinder thermostat and motorised valve, and you will have constant hot water.
You have the choice of mains water pressure more expensive, or low pressure cheaper.
I had a boiler tankless when I moved to the current home. The boiler tempature had to be higher to supply enough hot water to meet demand once mixed with cold water. I had a layout to allow any option but after research decided on indirect. It keeps the boiler running fewer cycles, has a long guarantee, uses minimal parts to create the zone with controls that are standard and of course lowers the boiler tempature to save oil. All this with the addition of outdoor reset makes this 5 year old boiler as efficient as can be.