Adding a Heat Pump and Other Energy Upgrades
We bought our house last Monday! We know it pretty well because we’ve been renting it for six years.
Our old gas boiler stopped working on Friday! Now we are true homeowners – it’s 15F outside and we’re living on space heaters.. 🙂
I had visions of carefully planning out a green retrofit. If the gas boiler can’t be fixed, we will have to greatly accelerate that.
Seems like yinz enjoy a puzzle, so here’s mine – all advice welcome!
Our house was built in 1947 on a concrete slab, with a footprint of about 1000 square feet plus an improved attic. We will add insulation where possible this year, but with the improved-attic ceiling in place and some questionable roof ventilation, we may have insulation limitations for many years. The south roof is partially shaded by neighbors’ trees, so I am dubious about adding solar panels. Small detached shed, no garage, and we’re perched at the top of a little ridge, so no place to drill geothermal. We’re in the Maryland suburbs of DC (IECC Climate Zone 4).
Our malfunctioning ancient gas boiler is in a tiny utility closet in the center of the house. The boiler feeds hydronic floor heat plus a hydronic air handler that sends air heat through ducts. Our aging central-air condenser uses the air handler and ducts as well. We enjoy the warm floors but we also like the air heat so we can have a cooler house for sleeping, then a quick burst of heat when we wake up.
That tiny utility closet also has an ancient gas hot water heater. Our hot-water use is average – one shower but several users.
I’ve read the debates about various ways to help the environment, and our choice is to phase out all fossil fuel use, if at all possible. We are willing to pay more for electric. The only way we’d buy a new gas unit is if we can’t find a local contractor to install and maintain the needed electric unit. Circuit box says 200 amps – we seem to have plenty of room for more electric use.
I’ve been told any new gas equipment in our tiny utility closet would require re-doing the ventilation because what we currently have is not up to code. With any type of new units, we may need small options to fit the closet.
We would like to keep the radiant floor heat, but if it’s likely we could insulate the slab and floors sufficiently for the floors to be room-temperature, instead of cold, we would consider abandoning the radiant heat.
We may need to break up the work into phases to spread out costs. And if our gas boiler can’t be fixed, we may need to address heating first and quickly.
So for air heat, would you use a heat pump with our current ducts? Or use a mini-split and close up the ductwork? It would be great to get rid of the huge air handler in our attic eaves, as we could really use more storage space. Any other green options?
For the radiant floors, I’m dubious about maintaining a solar thermal system – will it be worth the expense and maintenance? We could get an electric-resistance boiler, but the electricity will be expensive for what we get. How well would floor insulation work – should we just abandon the radiant floor system? What would you do?
For hot water, a heat-pump water heater would have to be inside our heating envelope, though maybe we could duct it up the chimney currently used for the gas units? And we would have one with electric-resistance backup – would that cover us on cold days? Would that complex heat-pump water heater design still be better than a simple electric-resistance heater? Any other options?
And finally, how do I find the local contractors who will do these green retrofits on a moderate budget? Should I hire a consultant first? I see energy auditor online, but few claim to advise on major HVAC issues. And when I look at the local HVAC companies, they do mini splits, but no one mentions installing electric boilers or anything unusual. I’m enjoying the many innovative ideas written up on greenbuildingadvisor.com, but how do I actually get something unusual installed?
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