To move a H20 tank, go Tankless?
AaronRosenthal
| Posted in Energy, Heating & Insulation on
I’m doing a rebuild of my basement suite, and my water tank has become a problem. 50 gal gas, 2 1/2 yrs old, sitting beside the chimney in the center of the basement. To change it after malfunction, I need to open a wall in the suite, then drag it through the suite to exit, reversing the process to install a new one. Because of an intervening staircase, it’s the only way to access it. I could relocate it to an exterior wall and live with the longer runs, but I’m interested in the comments here. I can budget for a new tankless unit or just move the existing one. I’m NOT necessarily trying to save running costs, but make sure a tenant and my family (2 adults, 2 teen boys and a 3 yo) all have enough water.
Replies
A TWH serving two ocupancies? Doubtful.
It can be tricky with just one family using it--sometimes you need to wait to fill the washing machine till everybody's out of the shower.
Is there a furnace in there also that might need changing sometime? Maybe you need to create a permanent access to the space anyway.
A TWH large enough to handle the load (7-10 gal/min @ 80 degree rise) might very well need a larger gas line and a larger flue, although some models vent in PVC, but, still, it might be more trouble than you want to make the change.
You could go to a 75-gal tank with 50k BTU input, and would end up with a first-hour capacity of over 100 gal.
I'm not a big fan of
I'm not a big fan of tankless, but everything has a time and place. I disagree w/ the other poster, though that a tankless would have problems. The right choice of tankless can give you 'endless hot water'. Down side is the installed cost. As you elude to ... the energy aspect is minimal ... particularly w/ your situation ... energy savings would be miniscule. You may have a space problem that a tankless might solve. Your tankless may require larger service (elec or gas) which may increase installed cost. You can get tank style in enough capacities to match your needs (assuming as you said, you can get it in/out); setting the right temperature will balance your demand and your capacity.
Agree that you may have a space problem that a tankless would solve, but if it's in the basement and the vent is on the roof, you'd better price out the flue material first. My own tankless uses category 3 stainless flue and it is expensive, even for the very short run I built. If you already have a perfectly good unit and could relocate it, I would probably do that and look into re-running some of the supplies in 3/8" PEX or other pipe to speed up the delivery times. That said, a tankless is a great way to solve a space problem... ours is in the attic.
Mr. Meiland brings up a good point re: the flue. If that is the case, consider a condensing style high efficiency model tank or tankless that can vent out a sidewall using PVC/ABS. The equipment cost goes up a lot, but it may be worth it if you have a lot of flue to install ... plus the efficiency will benefit you in reduced hot water bills.
Thanks for the input.
In either case, moving the existing tank or installing a tankless, I will need to install a flue and change supply lines. My flue would exit out the side of the house in both cases.
If your flue will exit through a wall, you can forget tankless. Flue gas temps are very high, which becomes a danger to people and any nearby plants.
Being on the west coast, you may want to go with a high efficiency 50 gallon (google Polaris for an example) which will give you 50 gallons of potable water in the event of a serious earthquake that damages city water pipes.
Those units run flue gases through stainless tubing inside the water tank to capture waste heat, resulting in 140˚F flue gases that can be safely vented through wall or ceiling via 2" or 3" PVC or ABS pipe.
The down-side to them is high burner rate (130K to 175K BTU/hr) that may require bigger gas lines from meter to WH, and positive vent blower that means the WH won't heat if the power is out.
Thanks for the input.
In either case, moving the existing tank or installing a tankless, I will need to install a flue and change supply lines. My flue would exit out the side of the house in both cases.
They make sidewall discharge kits for tankless. But you do need to be care full where they discharge.
And for tank type you have a couple of options. I just installed a sealed state Direct Vent. That comes with the coaxial flex vent pipe and termination.
And then there are the power vents. They use blowers and PVC piping for the discharge (and inlet if they are of the sealed type).
Aaron:
This is a little off topic but I don't like standard vent gas HW heaters in or near living areas because of the possiblity of backdrafting etc. Get a direct vent.