FredT
Guest
I have a tankless, and a tank heater. The tankless heater is good for a particular change in temperature at max flow, mine is good for up to an 80°F rise over incoming. Since I need at least 160°F in the mains for blending water to the handicapped bath to allow for realistic tub fill times I have the tank heater feeding it set to hold @ between 80 and 90°F. It rarely lights off between May and October.
If I was doing it again, (or when I can access the attic again) I would put a circulating pump in at the far end of the line, set to a timed cycle on a motion sensors located in ALL the bathrooms. That way when a bath is occupied the hot water is there, when it's not the pipes and heater can rest. The handicapped blending valve thing means my hot water lines are all 1", so the volume in them is significant. A circulating pump and line between the blender and the hot water pre-tank would save me about 4 to 6 gallons every time my mother-in-law needs to wash her hands. The water use isn't an issue as we are at the bottom end of the aquifer and anything we don't use bubbles up in FW seeps in the Gulf, but the sewage charges at 4X treated water rates are killing me.
The things I learned:
1. Burn outside air if gas fired.
2. Electric ones take multiple BIG feed wires. The one I had planned to use in my mother-in law's bath to avoid the blender took 3 independent 240V circuits of 2 ga wire. The copper and breakers to feed that thing at over 120' of run to the main panel would have cost about twice what the whole house tankless ran.
3. We put it central in the house when we rebuilt. Better to offset to the heaviest usage.
4. The tanked pre-heater set properly is not a high operating cost issue if properly insulated. If I can ever get a solar system installed it'll be run off the tank, with the tankless being make-up. As it is the tank is make-up.
5. Gas fired ones ARE NOT quiet. 45db is impressive at 0300, even if you can't notice it during the day. This is fine with me as it notifies me when my occasionally delusional mother-in-law is active in the middle of the night (Parkinson's meds are often a bit like weak brown acid), but needs to be remembered if dealing with a nursery on the other side of the wall.
If I was doing it again, (or when I can access the attic again) I would put a circulating pump in at the far end of the line, set to a timed cycle on a motion sensors located in ALL the bathrooms. That way when a bath is occupied the hot water is there, when it's not the pipes and heater can rest. The handicapped blending valve thing means my hot water lines are all 1", so the volume in them is significant. A circulating pump and line between the blender and the hot water pre-tank would save me about 4 to 6 gallons every time my mother-in-law needs to wash her hands. The water use isn't an issue as we are at the bottom end of the aquifer and anything we don't use bubbles up in FW seeps in the Gulf, but the sewage charges at 4X treated water rates are killing me.
The things I learned:
1. Burn outside air if gas fired.
2. Electric ones take multiple BIG feed wires. The one I had planned to use in my mother-in law's bath to avoid the blender took 3 independent 240V circuits of 2 ga wire. The copper and breakers to feed that thing at over 120' of run to the main panel would have cost about twice what the whole house tankless ran.
3. We put it central in the house when we rebuilt. Better to offset to the heaviest usage.
4. The tanked pre-heater set properly is not a high operating cost issue if properly insulated. If I can ever get a solar system installed it'll be run off the tank, with the tankless being make-up. As it is the tank is make-up.
5. Gas fired ones ARE NOT quiet. 45db is impressive at 0300, even if you can't notice it during the day. This is fine with me as it notifies me when my occasionally delusional mother-in-law is active in the middle of the night (Parkinson's meds are often a bit like weak brown acid), but needs to be remembered if dealing with a nursery on the other side of the wall.
