Home Improvement → Re: Anyone have a suggestion for standby whole home generator?

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The cost of a flue, propane furnace, hookup to 2 air handlers, carbon monoxide detection, and maintenance would surely exceed any savings for a few days of power outage.

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You may be surprised. That's why I advised you to at least "look into" using propane furnaces rather than electric resistance furnaces as backups to the heatpumps.
The operational limits of air source heatpumps tend to be greatly exaggerated (especially by their fanboi's on this site). While they are great if you live in a milder winter climate, they lose efficiency fast the colder it gets. Trust me, it will be well above -10 when the air source heatpumps will not be able to keep up with your heating demands by themselves.
You should consider the cost of propane / btu vs. electric / btu only so far as the "auxiliary" heat is concerned (resistance heating).
Naturally, a power failure is most likely to occur during extremely inclement weather (coldest or hottest).
Unfortunately, the price of propane isn't nearly as stable as electric rates, but both are subject to fluctuation.
This "dual hybrid" scenario actually makes a lot of sense when a generator is thrown into the mix.
The potential for savings isn't going to be just "generator" time, but any time in the colder months when the auxiliary heat must fire up to keep your house comfortable. This is going to happen a lot more than you might expect.

The main problem I have with propane is the propane mafia. If you're going all in with propane and lease your tank be prepared to call your propane company every season and haggle.

Otherwise be prepared to pay megabucks to install your own tank.

Megabucks? Hardly. I paid $1800 for the underground tank and $400 for installation. That's hardly megabucks compared to what I've saved vs a leased tank in 3 heating seasons.

I've had a Ruud 14 SEER heat pump for about 7 years (forget the heat pump spec, but the AC is 14 SEER).

Last year, on all but 1 day, in Connecticut we survived without auxiliary heat. Auxiliary heat was on for about a 6 hour period a few hours before and after dawn.

I've kept my home at 77F in winter at 10F outside with the existing Ruud. Our new heat pumps are somewhat newer, have improved performance, and will be installed in a better insulated (though much larger) home.

If the heat pumps fail, and I spend thousands of dollars on resistive heat, I'll investigate a propane auxiliary heat system.

Though I appreciate your help. It is my amazingly positive experience, with a now somewhat older heat pump, that causes me to have some confidence in the newer units.

The issue isn't "if" the aux heat will kick in with the heat pumps running, it's "when".
Heatpumps *must* defrost the outdoor unit every so often when it's cold. This can be triggered via a mechanical timer or an ice sensor. Sometimes they need to defrost every 30 minutes.

During the defrost cycle, the compressor reverse cycles and the indoor heat strips will come on (they have to).
Up until now, things have been hunky-dory. It's 20 degrees outside. The generator has been running about 40 minutes. You're snuggled up with the wifey sipping brandy and laughing at the neighbors - then suddenly the generator bogs down and the lights start to flicker...

This is the point where you got screwed by your electrician: You have to anticipate the compressor AND the heat strips running simultaneously.
Going off the manufacturers cut sheet, your 4 ton unit is going to be drawing about 3.8 kW (avg), and require a minimum heat strip of 10 kW (unfortunately it looks like it might actually need a 12.5 - 15 kW for an effective defrost call from the HP). Throw 2 of these units into the mix and you see the problem... right? 13.8 kW x 2 = offline genset. Even if you only run one of the units, it leaves you very little wiggle room for all of your other household needs (lighting, computers, pumps, TV's, etc...).
Your generator probably won't cut it at 20 kW. If you have gas fire instead of electric heat strips, you can see how that rectifies the situation.

I think your electrician probably failed to take this into consideration.

I shall see what happens and report back. If eating of crow is necessary, then I shall dine upon it, while investigating a propane furnace.

A propane-fired tankless heater + hydrocoils probably costs less than the difference between a big-ass generator and a smaller one that has no issue running on emergency heat.

I found this website that offers an assortment of hydrocoils:

»www.altheatsupply.com/sh ··· ers.html

I wonder if a tankless water heater would be able to supply sufficient heat. My Brother In Law used a quick recovery storage type water heater with a 75,000 BTU burner like this one:

»www.lowes.com/pd_89263-1 ··· cetInfo=

It heated a home office in his attic and provided hot water to a collocated bathroom. His costs were different because he used natural gas for heat.

Something like this should have no issue: »www.lowes.com/pd_364960- ··· _price|0

I had auxiliary heat from hot water. I won't be running anti-freeze filled lines to my attic again. I've been there and done that.

Thanks for the though though.

I appreciate your help, but my mind is made up for the moment. If the system doesn't work, I'll write back and explain the failure. Time will tell.

Have the new heat pumps been installed?

If not, why not ask your HVAC contractor for a modified quote on at least one unit?

It doesn't have to be anything fancy, but it would be easier on any genny to off-source the heating load to a furnace.

It sure is nice to have A/C, but I'm guessing in your climate having heat probably a little more important than having A/C.

I agree with you about the tankless/coil - and am very thankful for my basic, does-not-need-electricity water heater which burns cheap natural gas.

My new electric hot water heater is a Geospring. Not certain how expensive it'll be to keep.

Three of the happiest days in my life recently was the day my oil furnace and related hot water heater were removed, the day my chimney was removed, and the day the two 330 gallon oil tanks were removed.

I'm off oil, and am happy. My electric rates are much more predictable. The 2nd generation Geospring seems to run well. Supposedly it costs about half as much as a conventional electric hot water heater. My understanding will improve better over time.

My last go at oil heat was a System 2000, which had to be repaired about 5 times over an 8 year period.

Our heat pump has worked well in winter and summer.

We shall see what happens. I understand many are better informed than I can be, and are probably much smarter. For better or worse, in my home, at least immediately after this renovation, it'll be heat pump, electric auxiliary heat and a Geospring (second generation) providing hot water.

I don't want to worry about oil tank level, or how much oil will cost for the next 400 gallon fill.

Ummm...the first generation Geosprings have some pretty terrible reviews as to their performance & reliability.

E.g. poor recovery vs. conventional tank, interminable wait for parts (30+ days).

Note that these type of water heaters offer better performance in a hot climate like mine vs. a cold climate such as yours.

Be sure to buy the extended warranty - looking at online discussions you'll probably need it.

Was it your choice or suggested by your contractor?

I have 10 years warranty from Lowes. My contractor only understands basic devices. The Geospring was his first.

Often when dealing with trades people, I feel like it's 1960. Many do not understand Internet, a number of electricians did not understand my desire for Cat 6 wiring, two suggested everyone uses wireless.

I tend to like new technology, the 2nd generation Geospring seems nice.