Home Building Questions - Propane - All electric - Fireplace

[kenmac]

If you have a tightly sealed house with very low infiltration rate and you have a gas water heater inside that envelope, that may be a problem. When you turn on an exhaust fan in the bathroom or the kitchen, where does the makeup air come from? That gas water heater exhaust pipe is basically a hole to the outside and can have air sucked back down the exhaust pipe.

I have seen this happen, but not from a fart fan. Except where the WH was installed in a bathroom with the door sealed off and closed

could it happen with A whole house exhaust fan ? possibly.
it all depends of how large the home is, and what the cfm the fan is

 

[ponytug]

I'm also going to call and check on Geothermal vs Heat pump VS AC with propane furnace with a local HVAC company that has experience with all of them. My initial research looks like Geothermal may be out of the running because of up front cost.

While I think geothermal heat pumps are wonderful, I would do a cost comparison, and an efficiency comparison between air sourced and geothermal sourced heat pumps for your site. While geothermal had large efficiency advantages over air sourced heat pumps ten years ago, the efficiency advantage has really dropped. In my area, despite great soil, and well opportunities, geothermal never wins on a cost comparison. (Don't forget to factor in the running costs on the geothermal circulation pumps, and fluid changes.)

If you have a tightly sealed house with very low infiltration rate and you have a gas water heater inside that envelope, that may be a problem. When you turn on an exhaust fan in the bathroom or the kitchen, where does the makeup air come from? That gas water heater exhaust pipe is basically a hole to the outside and can have air sucked back down the exhaust pipe.

With a well sealed house, you can, and probably should put in a heat exchanger for the exhaust fans to provide conditioned make up air. There are fancy ones that can humidify/dehumidify the make up air.

One fringe benefit is that they get the fan away from the bathroom or kitchen fan, so they are nearly silent. My folks put one in when they built a new house awhile back, and it was wonderful.

@LittleBittyBigJohn Personally, I am not a fan of on demand water heaters; they have a minimum flow rate to turn on, and intermittent usage, like hand washing, often means either cold water, or wasting a slug of water to get the hot water there. I prefer a recirculating pump on a timer to keep warm water at all fixtures.

I will say that PEX piping makes an enormous difference as the dead volume of PEX piping is much smaller, and more of it tends to be piped off of manifolds so that you get your hot water faster. I prefer the ProPex (upnor) style fittings as you get the full diameter of the pipe for best flow.

All the best,

Peter

 

[t1kilo]

If you have a tightly sealed house with very low infiltration rate and you have a gas water heater inside that envelope, that may be a problem. When you turn on an exhaust fan in the bathroom or the kitchen, where does the makeup air come from? That gas water heater exhaust pipe is basically a hole to the outside and can have air sucked back down the exhaust pipe.

The Westinghouse propane condensing water heater that I mentioned in a previous post has two PVC pipes connected to it. One is the exhaust pipe, but the other is an outside air intake. I agree that a conventional NG/Propane water heater could be a problem inside the envelope of a highly efficient home.

 

[KennyG]

I believe that code now requires an outside air intake for ventilation if the building has combustion devices that use ambient air. It's simple to arrange this with a "trap" so that only the necessary amount of air enters the house to keep it from going to negative on pressure. I have these in my house and, in winter, they always have small flow into the basement to balance the inevitable leakage of air out the upper portion of the house.

 

[dodge man]

Before we switched to geothermal our LP furnace and water heater had fresh air intakes. Wasps built a nest in it one time and screwed things up until they found it.

Im going by memory here but I was thinking the AC side of out geothermal was where the biggest payoff was. Just a guess on my part but the OP is in central Arkansas so the heating side of the geothermal may not payoff as quick as the AC side.

At one time I saw a spread sheet someone posted here and you could play with the various costs of heating methods. As I recall natural gas and wood were both very good. That was assuming you had to pay for the wood. This would be an outside wood boiler. LP works well but the price can be erratic. At one time we paid over $5 a gallon. That one hurt.

This is one of those things there is no right or wrong answer. An HVAC expert can give you the best answer for you though.

 

[Locoweed]

I have been charged $.30+ a kilowatt a time or two. I didn't like that much either.

 

[dodge man]

I think we are paying about 15 cents a kilowatt hour. We have a separate meter for the geothermal and I think it’s about 3 cents less.

 

[Gem99ultra]

I would go to a propane unit that doesn't require electricity to provide heat;it will be your back-up.Pellet stoves require some-one to clean and feed them(40 lb.bags) and store the pellets.

Propane will probably be the cheapest. We have both propane and electric heat. One major drawback to using propane for heat is the residue that ends up on every wall, ceiling, and furniture. Small undetectable at first, but after a couple of years - you'll see and feel it.

This winter we've gone to all electric heat. The cost will be higher, but I don't know yet exactly how much higher. Regardless, paying a higher electric bill is cheaper than getting a new wife!

 

[Carl_NH]

At one time I saw a spread sheet someone posted here and you could play with the various costs of heating methods. As I recall natural gas and wood were both very good. That was assuming you had to pay for the wood.

Hi Dodgeman - I posted one in another thread - here it is below - you should be able to copy and paste this into excel. You also need to input your local cost for the heat type - this is what the various fuels cost here this year in NH.

Also, you can add a load column to this BTU/Hr expected demand which can give you a rough order of magnitude cost to operate for a day.

FUEL	ENERGY CONTENT		UNIT PRICE		HEAT CONVERSION EFFICIENCY		COST PER MILLION BTU
Kerosene	130,000​	BTU/gal	$4.05​	/gal	91	%	$34.23
#2 Fuel Oil	135,000​	BTU/gal	$4.00​	/gal	89		$33.29
Propane	92,000​	BTU/gal	$2.69​	/gal	94		$31.11
Natural Gas	100,000​	BTU/therm	$1.79​	/therm*	94		$19.04
Electricity - Resistance	3,412​	BTU/kWh	$0.34​	/kWh**	100		$99.65
Electricity - Heat Pump	11,945​	BTU/kWh	$0.34​	/kWh**	100		$28.46
Coal	13,200​	BTU/lb	$300.00​	/ton	75		$15.15
Firewood-Hardwood	25,000,000​	BTU/cord	$375.00​	/cord	60		$25.00
Wood Pellets	8,200	BTU/lb	$350.00	/ton	85		$25.11
Shelled Corn	6,800​	BTU/lb	$6.00​	/bushel	75		$21.01

 

[LittleBittyBigJohn]

That's a nice spreadsheet!

I just worked up my cost per KWH from my last bill. I'm paying just under $0.11 per KWH including all fees and taxes.
Propane is around $2.39/ gal.

Just a quick glance at this looks like all electric will be cheaper.

All electric and a pellet stove is feeling more and more like the way to go. Maybe I'll install 2 water heaters to solve the hot water issue?