What Backup Other Than Oil or Propane?

[velvetfoot]

Oil and propane here (near Albany, NY) are so darn expensive, I wouldn't mind getting away from oil for backup/supplemental heat and domestic hot water. We have an oil hot water boiler and indirect tank for dhw.

What are the alternatives? Is there such a thing as a heat pump for convectors?

 

[woodgeek]

Doubt the FHW radiation can be used with a HP--the water needs to be 140-160°F to deliver--and that is too hot for a HP to produce, at least with any efficiency.

There have been a few threads here about ductless mini-splits (heat pumps) for supplemental heat, very cheap to run in the shoulder season, still cheaper than oil in cold weather. With FHW, I assume you don't have ductwork for central A/C that could be used? Not needed for mini-splits.

For DHW, there have been some threads about heat-pump based water heaters--search for geospring. Cost a few $k, and suck heat/moisture out of the conditioned space they are located in. If you have a large semi-conditioned, unfinished space for it, they cost 50-65% less to run than an electric.

Both upgrades can be done separately--and should have good ROI relative to present oil prices. The mini-splits are very good for wood burners as they cover the shoulder season easily/cheaply.

 

[EatenByLimestone]

How about electric. It's not cheap, but backups aren't intended to be used...


Matt

 

[Ehouse]

I put in a propane boiler (used of course), with an indirect and 5 zones on the manifold. I ran a 1" pex line loop around the basement with the intent of using radiators off monoflow tees. Then the price of gas shot up and I couldn't find any rads at a bargain price. I happened across a Toester 2 speed kick space heater at a lawn sale for 10 bucks. It's rated for 11,000 BTU on high. I then found a Dayton Hydronic unit heater rated at 40,000 BTU (fan coil garage heater) like new for 100 bucks. I cut the kicker into the main loop with monoflows and put the Dayton in my oil furnace plenum after removing the blower and making an interface plate. The fan on the Dayton is rated for constant duty so I put it on a vari-speed fan control. this worked like a dream to heat the house. With the fan control at about half speed the existing duct work distributed the heat evenly and quietly with the cold air returns ensuring circulation. The kickspace heater (also a fan coil) is on an aquastat and a low/off/high switch. The main loop is on a thermostat on the main floor. Nice as this was, I was using a lot of propane, so I put in a small wood stove. Being a tightwad, I didn't want the whole boiler system coming on when the wood stove wasn't keeping up, like in the mornings before I could get it cranking. I put a shutoff valve after the first monoflow tee to the kicker and ran the return to an unused return space on the manifold. This let the Kicker be on its own loop off the main zone using the main thermostat without running hot water through the whole loop or having the Dayton come on (Vari-speed off, Shutoff closed). To activate the system I turn the main thermostat up and get instant heat from the Kicker. If I need to I'll go down and open the shut off, turn up the vari-speed, and on comes the Dayton. The whole point of this is that you can layer your system to suit your various heating needs without having your whole system come on. Gotta go.

Ehouse

 

[Ehouse]

To finish up this ridiculously long post, I say, use your existing system and break it into smaller units. Fan coils are one way to get a lot of fast heat where and when you want it.
Ehouse

 

[velvetfoot]

In my setup, the wood insert heats the main floor (colonial) and the wife turns on the oil to heat the upstairs, and there's the hot water heat too, so it's actually more supplemental than backup I guess.

I wouldn't have thought either that a heat pump kind of unit could get water hot enough, but there are those heat pump water heaters now-not sure how how they get, but I bet it's close.

 

[velvetfoot]

I'll do a search on those mini-splits too, thanks.

 

[woodgeek]

While you can def heat your house using a hot water heater and your FHW radiation, the HP DHW heaters won't work for an obvious reason--they suck the heat from the living space, not outdoors. It's a closed system, pumping heat from one part of the house to a different part. I'm sure you already thought of this. Because they have no defrost controller/function, they can't draw heat from a space colder than 40-50°F.

The coefficient of performance (COP), basically the % efficiency/100 is ~3 pumping heat from 60°F to 110°F, and drops rapidly as the temp difference increases.

 

[Highbeam]

In the abscence of natural gas, your only option remaining is electric. If this is really for backup heat then electric is best delivered to your living space with the 220 volt wall heaters. They are great because they are cheap to buy, easy to install, and each one is on its own thermostat. The electric water heater is a traditional choice that has proven to be very acceptable, silent with no exhaust fumes or user input.

Is your electric prohibitively expensive? You could heat with pellets and heat water with electric.

 

[bbeals]

We run a Jotul Rockland 550 for our primary heat source, Trane XL15i Heat Pump as secondary, Lennox oil burner as our final backup and pray like hell it never runs...We back all of this up with a Kohler 14KW propane standby generator (gots to run the blower fan on that jotul)

 

[billb3]

in the absence of natural gas I've gone with solar panels for DHW (panels are not up yet) and the most efficient oil burner I could afford for both back-up and back-up DHW. Electricity is way too expensive here to even consider.
Except for needing a chimney removed and some minor structural repair I have a perfect roof -due South, nice pitch for solar.

 

[Don2222]

Hello

My Keroheater I call "Stinky" makes a good backup especially when there is a power failure! See pic below in Home Depot!

 

[Highbeam]

Cost of installation and required maintenance (dependability) is more important than operating cost (fuel) with a backup system.

 

[Ehouse]

In a hydronic system, If you increase the size of the radiator, you can lower the operating temp.. Increasing the flow rate also delivers more heat to the living space for a given temp.. design temps. for radiant floors can be as low as 80 degrees. An option could be radiant wainscoat or ceiling (DIY) fed by an air to water heat pump.

Ehouse