HVAC in New Construction in 2024

The blower on the burner is about 100W. Fuel pump is 10-20W. Zone valves also use power (some less then others). ECM pump when pushing pressure will also use more. Most around me that I have seen have 3-5 non-ecm pumps. Adding it all up, 200W is on the low side. Running a boiler uses real power, ask anyone off-gird.

Nameplate efficiency in the field of any boiler is highly optimistic and assuming 2cop for heat pump is on the bottom end. Even with those assumption the operating cost is close enough not to matter. Get a decent equipment and decent install with a ASHP and you are still ahead even with expensive power.

Once you need AC, the maintaince cost is about the same as a heat pump. A heat pump is actually less usually as it is much easier on parts since it is inverter controlled and there are no hard starts. With dual fuel now you still have the extra maintaince of the boiler plus the cost of buy/install. No matter how you cut it, the maintaince will be higher for any duel fuel setup.

@mattmich I have built that exact setup for my home. Beside the 3x install cost, it feels like it should work well but doesn't in the real world. PM me if you want details.

In any place that needs AC (which is now the cases even in great white north up here), hydronics is dead as you have to install two complete separate systems to get AC. Any older residential hydronics around me is getting pulled out in most large renovations. It does not exist at all in new builds except for snow melt. The only place hydronics will stay is in the commercial world.

Removing a boiler or furnace without living though a typical winter with a heat pump and without review of forward looking electric rates is malpractice. And saving $1,000 per year adds up over the life of the boiler…and that's not adjusting for electric rates that are increasing at 15% to 25% per year in New England.

@Kaos , an oil burner is ON/OFF, so if the boiler is fired at 0.85 GPH for 700 gallons, that's 825 hours or about $50 per year in electricity at $0.30/kWh ($12/gallon equivalent per unit of energy, see above). The 2.1 COP (210% efficiency) is a seasonal COP from the Department of Energy Study for cold climate heat pumps selected for their top performance, and the 87% likewise reflects top performing oil boilers (top performing gas boilers may be slightly higher). Since that is an annual/seasonal COP, the COP is actually substantially lower in the cold of winter, making the heat pump option unaffordable compared to oil ($3.50/gal).

The Vermont Department of Public Service has warned the Public Utility Commission that cold climate heat pumps don’t always lower heating bills. Their analysis shows results depend on electric rates, and Vermont has the lowest electric rates in New England (where rates can be 30%+ higher).

@Kaos , it’s an interesting theory, but per the study: “Most of the all-electric sites had very few hours with outdoor temperatures below the compressor lockout temperature.” This is the maximum outdoor temperature at which the auxiliary heat source operates, so it will not run unless it’s very cold out. The auxiliary heater ran 4.8% of the time on average at these sites.

“Additionally, all the sites were in dry climate zones where the need to defrost the outdoor coil would be much less than that of heat pumps installed in humid or marine climate zones.” We could expect the efficiency to be worse on the east coast, especially near the Atlantic or where it is more humid in the summer.

Thank you, @mattmich - I should have been more clear as that is actually 4.8% of the time the systems were monitored during the study, not of the entire year, but still about 200 hours in a heating season. The vast majority of the energy consumption is from the compressor.

To your point about stressing the grid, adding heat pumps will need to triple the size of the residential grid power supply in cold climates, and adding electric vehicles for each home will move it to 4X - that's a lot of pizza. Some states like Maine have electric grids that are already "winter peaking", using more electricity in winter than summer.