New boiler or strip heaters in existing heat pump air handlers

WMno57

I like systems that are as fault tolerant as possible. Better design so as to avoid cascading failures.
For an intermittent occupied vacation cabin in the north I would spec forced air or electric resistance baseboard. Not necessary in a full time home in Stamford Ct. You can keep everything inside the conditioned space of your home from freezing for a long time.
On cool days you enjoy the high efficiency of your heat pump. On cold days you enjoy the superior comfort of hydronic radiant heat. They back each other up. No single points of failure.
The sensibly sized generator consumes less fuel when needed. Your propane supply will last longer.
No glycol = less problems. Simple systems have less failure points. Less to go wrong. Cheaper to maintain.

Mathelo

Jamie Hall said:

Depends on how cold it gets and for how long, and if the system is running. If the system is running (pumps on) and the boiler is keeping up, they will only freeze in really extreme conditions -- continental US doesn't get that cold (northern prairie Provinces, northern Ontario and Quebec, inland Alaska do!!). But if the water isn't flowing, then insulation will delay things -- but won't keep them from freezing if it's cold enough long enough.

So I need to come clean on the antifreeze in my system. While it did have antifreeze in it when first setup some 25+ years ago, and I just had it recharged last week, it has NOT had any antifreeze in it for the better part of 20 years or more. My oil company technician asked me if I liked living on the edge. I guess I've been lucky. Having said that I was always aware and I made a point of turning heat up on really cold nights. Not a great plan, I know.

Mathelo

WMno57 said:

• Option D-A hybrid
  
• New small Boiler (heats basement and 1st floor
  
• 1 Propane Forced Air Furnace in attic for 2nd floor
  

More expensive than D. Better 2nd floor heat than D. Heats basement better than A.

Where would you expect the propane forced air furnace in the attic to be placed relative to the existing air handler? Does it simply get added on one end? And does no one here have any concerns for propane in the attic? If there is a propane leak, it will settle down into the house. Of course, I imagine that isn't much different than the range in the kitchen that is over the basement.

Hot_water_fan

Where would you expect the propane forced air furnace in the attic to be placed relative to the existing air handler? Does it simply get added on one end? 

This is an extremely common set up - much more so than a hydronic air handler. Your installer should know how to do this. 

WMno57

Usually the forced air furnace includes the air handler or fan. The AC coil is placed on top of this in a basement updraft unit. An attic furnace would be a sidedraft unit, and the AC coil would be downstream. No one designs a clean sheet of paper basement home with an attic furnace. Even slab foundation homes usually have an updraft furnace in a closet with just the ductwork in the attic. Attic furnaces are uncommon. Heat rises, so better to have forced air heat ducts in the floor than ceiling. But older hydronic homes don't have ductwork, so we have to compromise. Heat pumps also have to compromise duct placement, i.e. do you optimize ductwork for heating or cooling?

There is no single right answer for you and your home. Important considerations are what you are comfortable with, and what your contractors can install and support. My suggestion is still Option C (which has no propane or water in the attic). But we are not here to sell you. We are here to explain options, and help you make the decision that is right for you.

Mathelo

Jamie Hall said:

50 K BTUh is 15 KW. 62 amps at 240 volts. Do you have the power in your main entry? In your switchgear? And how are you going to power those strip heaters when the power is off and it's really cold -- which is when you will need them. Just asking...

Shouldn't I be able to handle this with a large portable generator? There are 20,000 watt portable generators available. If my math is right, that should cover it.

Mathelo

At the risk of going down the proverbial rabbit hole ...

What boiler would you recommend if I step down from the System 2000?

Long Beach Ed

You must clearly define your priorities to make this decision. Is it cost? Initial or ongoing? Reliability? Sustainability? Service life? Virtue signalling? Newest and best? You then have to make certain "guesses" about future resource costs.

Reliability comes first in my book, along with ease of emergency operation. I see our utility grid and political climate as depreciating rapidly, becoming less reliable in the future, so some versatility is important to me. I dismiss most higher-cost trends being pushed these days if they offer no clear benefit to my family or finances. I avoid any technology that reduces reliability or complicates service or access to service parts. I want heat when I need it and I'm willing to pay extra for dependability over all else. That's me.

If immediate cost is a priority, consider some very generous state and utility subsidies for converting to fully electric heating. I don't know if Connecticut offers such things, but in New York numbers like $20 - $50,000 are being considered for close-future state/utility programs. Unfortunately here, the increased ongoing costs would quickly eat that up.

My personal opinion would be based on my projected stay in the property. Unless I was moving soon, I'd install a boiler. It would permit me to have heat if/when your state joined the "rolling blackout club" and provide some shopping choice in fuel cost. Since boiler use would be somewhat limited, I'd install a very basic, less efficient boiler to assure reliability and permit operation with what could be "dirty" electric backup power. That would also help contain initial and service costs.

Define your priorities and go on from there.

WMno57

Mathelo said:

Shouldn't I be able to handle this with a large portable generator? There are 20,000 watt portable generators available. If my math is right, that should cover it.

I have a 16 KW Generac. It came with the house. It is ridiculously oversized and consumes too much fuel. True heat redundancy must cover mechanical and electronic failures of the heat pump.

Jamie Hall

Mathelo said:

Jamie Hall said:

50 K BTUh is 15 KW. 62 amps at 240 volts. Do you have the power in your main entry? In your switchgear? And how are you going to power those strip heaters when the power is off and it's really cold -- which is when you will need them. Just asking...

Shouldn't I be able to handle this with a large portable generator? There are 20,000 watt portable generators available. If my math is right, that should cover it.

Yes, it would. If you are talking about a heat pump, though, be sure to check the starting current. Some have a high starting current which a generator may have trouble with.

As @WMno57 said above, though -- the big generators (we have two) are fuel hogs. At near rated power, they're pretty good. If it's idling along powering a few light bulbs, not so much. Something to keep in mind. Further, they are far less efficient, even at full power, than even a very basic boiler (any fuel) would be.