Hot Water Consumption Discussion

[BigNumbers]

All I meant with my comment was that t your house requires X amount of heat to stay at the temp you want, during heating season...

To the extent you use more energy heating water in a tank and the water cools, that heat is now in your house, so it wasn't really "wasted", the waste heat was just effectively used to heat your home - so really there is not as big energy savings in Canada going tankless as opposed to the southern US, for example, where every bit of waste heat is additional cooling btu's you need to use. Obviously you still win on whatever efficiency delta there is between the heat generated by your tank and tankless, but I am merely pointing out that the "efficiency" gained by going tankless is partly offset by this radiant waste heat the tank put out resulting in running your furnace more when you run your furnace - that's all.

I was just thinking about it from a physics perspective, that "waste heat" from things like LED bulbs and tank'ed HW heaters really just mean that your running your furnace more. You still win, but it's now an efficiency delta between the efficacy of incandescent bulb waste heat vs. a furnace and tankless vs furnace for waste heat.

[speede5]

I had electric and went to a 50 forced vent, Just couldn't afford the on demand at the time. Saw a considerable drop in my power bill, at least $40 a month.

My water heater never runs once it is heated up, at least not that I notice. It kept up nice with 5 of us in the house. Rarely ran out of hot water.

I still would do on demand in a new build but they are complicated units and I have heard bad things depending on how hard your water is. Also you really need to check your incoming water temp, In Canada in the winter it is quite cold and the on demand can only heat it up so much. This probably won't affect showering or laundry but dishwashers need water to be as hot as possible, so you may see some negative effect there.

I have built a couple basement suites for people who put these (on demand) in to handle the whole house and no complaints so far.

[calgarygeologist]

Originally Posted by speede5

I had electric and went to a 50 forced vent, Just couldn't afford the on demand at the time. Saw a considerable drop in my power bill, at least $40 a month.

My water heater never runs once it is heated up, at least not that I notice. It kept up nice with 5 of us in the house. Rarely ran out of hot water.

I still would do on demand in a new build but they are complicated units and I have heard bad things depending on how hard your water is. Also you really need to check your incoming water temp, In Canada in the winter it is quite cold and the on demand can only heat it up so much. This probably won't affect showering or laundry but dishwashers need water to be as hot as possible, so you may see some negative effect there.

I have built a couple basement suites for people who put these (on demand) in to handle the whole house and no complaints so far.

Don't dishwashers have their own built in water heaters for increased temperature?

[Canehdianman]

Originally Posted by calgarygeologist

Don't dishwashers have their own built in water heaters for increased temperature?

not all of them do.

mine does it when I choose "sanitize".

[Kjesse]

Thanks Fuzz, I was going to buy a recirculator this weekend. That plan is now cancelled.

[afc wimbledon]

It takes about 15 to 30 seconds for the hot water to get from my boiler to the bathroom, which is about the same as it did with the old tank, frankly it doesn't bother me at all, first world problem so to speak.