Propane/electric option for heating infloor hydronic

KenZakreski

After 20 years of my high efficiency condensing boiler (Glowcore GB090, 90,000btu) I'm replacing the heat source for my 3000 sq ft home (with 900 sq ft suite). The 2inch cpvc chimney will be replaced as well; but will keep the 2 inch intake outside air pipe. I have an indirect DHW stainless steel tank that I can keep, as it it in great shape (including Oventropp 3 way mixing valve, Grunfos pumps, zone valves with end switches.



My weird thing here is that I am on a small island in BC Canada so have :

a) cheap electricity say 8 cents per kwhr (half the heating cost of propane)

b) regular power outages when the snow falls (some lasting 32 hours)

c) expensive propane say $1.00 per litre with tank rental included.



I would like to add an electric heat source for the infloor because of the operating cost saving. Thinking of adding a commercial electric water tank heater to 6 kw or 9 kw (10-20 gallon). I have a 200 amp panel so that should be no problem. But must keep the gas as an alternative heating source. I have a small generator to run the pumps.



Does anyone know if there is a high efficient or mid efficient gas hot water heater (with side mounts for hydronic, power vented for 2 or 3 inch cpvc ) that also has electric heating with it (propane / electric hybrid water tank heater)?

Charlie from wmass

There are electric boilers.

I guess you answered my life long question of who would need an electric boiler.

KenZakreski

Space limits use of indirect tank for DHW

As the space under the stairs limits my use of a indirect fired tank for DHW I am looking for a combi heater for the gas portion of this system. If I can find one small enough (

TonyS

This might be

what your looking for

http://www.navienamerica.com/product/combi_01.aspx?skin=combi_01

KenZakreski

gas is for back up when power is out

This is a good tankless heater, but i was going to go with a tank gas water heater combi or electric DWH that can take indirect heating from the gas appliance.



the run to the roof for venting is about 25 feet plus two 90 elbows, the current vent is 2 inch pvc. I have 2 inch supply air pvc.



My understanding is:



1) tankless are noisy

2) I only need the gas heat as a boost for 2 months of the year and when the power is out for extended periods up to 32 hours

3) anything with micro processor controls will break, the power here is subject to brown outs

4) tankless will break and need repairs more often then tank models of equal quality

5) the advantage for tankless is there is no standby loss. My heater would be needed in the cold when the power is out or if the electrics can't keep up . The standby loss here tempers the house ventilation. As the heaters are under the bsmt stairs the  heat from stand by  loss is used.