"A furnace can brute-force heat. A heat pump can’t."
-Peak Comfort HVAC
If Part 1 was the “Should I?” for Ottawa, Part 2 is the “How to do it right.” Below is exactly how we design, specify, place, control, and commission heat pumps so they actually perform here, without the hype. We keep our stance consistent: we're pro heat pump, we advocate for keeping natural gas if you have it, and we obsess over proper commissioning.
Load calc & airflow: why heat pumps are less forgiving
On gas, even mediocre ductwork still “dumps” rated BTUs (it might trip on high-limit or shorten life, but it heats). A heat pump must move enough air across the indoor coil to move heat; if airflow is starved, capacity and comfort fall off a cliff. That’s why we size to real winter load, then set blower/CFM to what your ducts can truly support: balancing winter heat with summer dehumidification so we don’t oversize cooling.
Ottawa translation: We frequently check CFM and ΔT across the coil and tune the blower around the duct system you actually have, not a lab model.
Your ductwork decides how ambitious we can be
Ductwork is often the constraint. When it’s practical, we’ll open/upsized returns (often within ~15' of the air handler), add a dedicated upstairs return, and adapt the plenum/coil to let the bigger heat pump breathe. But we work in real houses with real budgets - if ducts cap the CFM, we’ll right-size the heat pump to that limit so you still get savings without noise or short-cycling.
We also run the regulated sizing tool and document the efficiency thresholds we’re targeting so your expectations match your home’s duct reality.
Defrost is normal (design for it)
In Ottawa winters the outdoor coil will frost; the unit periodically reverses, borrowing indoor heat to melt ice. You’ll see steam and hear a tone change: 3–15 minutes is normal. Cold-climate models add a base-pan heater to help drainage. We always mount on a proper stand, keep away from walkways (meltwater refreezes), avoid roof-shed, and plan a drainage path.
"If you see ice, don’t assume failure. Defrost is the system doing its job."
-Peak Comfort HVAC
Dual-fuel logic that actually saves money
In Ottawa, natural gas is cheap, so we almost always tell homeowners to keep the gas furnace and add a cold-climate heat pump. Let the pump carry shoulder seasons and milder days; gas covers the “ugly nights.” That’s by design, not failure. Field rule of thumb: ~45–50% less gas burner runtime ≈ ~30% overall utility savings on NG homes once the pump is doing the easy work (your house and ducts decide the final number).
Outdoor lockouts / switchover bands we like (tuned per house/curve):
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NG (ROI-first): lock out aux above roughly –12 to –15 °C.
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Propane: push deeper (≈ –22/–23 °C).
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Oil: run the pump to roughly –30 °C if the model supports it.
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Values-first electrification: run HP as far as it can; only switch when it can’t keep up.
"Yes, your furnace will still run. That doesn’t mean the heat pump failed. It’s the plan."
-Peak Comfort HVAC
Controls that keep modulation (and why we avoid Nest)
If it’s a communicating system, we use the OEM communicating thermostat to keep the full modulation you paid for. On many value-oriented hybrid set-ups designed for 24-V control (TXV indoors), Ecobee-style stats are fine, just commission them properly. We avoid Nest: weak commissioning tools and power-steal headaches are an industry-wide pain.
"Keep modulation—don’t “dumb down” a modulating system with the wrong stat."
-Peak Comfort HVAC
Equipment selection: what we weight (Amana/Daikin high-end, Comfort Aire value)
We spec Amana/Daikin as our high-end primary offering and Comfort Aire as our value brand, then choose specific models by looking at:
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Capacity & COP at Ottawa temps (not brochure numbers)—we want the actual BTU output and input power at sub-zero set points.
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HSPF for our climate zone (not a Florida number).
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Defrost quality (hidden variable; better models stay clearer).
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Cold-climate features (base-pan heat, controls).
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Parts support & warranty from brands techs are trained on.
We also call out “capacity maintenance” tricks on some value units that achieve big numbers by dumping wattage: great on paper, not on bills.
Outdoor placement rules (Ottawa realities)
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Proper stand above snow load; decouple vibration.
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Avoid roof shed and prevailing wind into the coil.
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Keep away from walkways and dryer vents; maintain clearances and a meltwater path.
Non-negotiables we won’t skip
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Brazing with nitrogen (protects modern EEVs/valves).
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Surge protection on inverter equipment.
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ESA permits pulled.
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Communicating controls where required.
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Full commissioning with photos and readings.
We leave a 58-point startup report—indoor/outdoor DB/WB, pressures, line temps, SH/SC, measured CFM/ΔT, evacuation microns, compressor amps trending, heat & cool startups, and a full hand-off. It’s baseline bloodwork for the system.
Quick FAQ (Ottawa)
Do I need 200 A to go all-electric?
Often, yes. On 100 A services we evaluate the whole load; many full-electric plans need a panel/service upgrade, which we’ll scope up-front (no surprises).
Will my furnace still run with a heat pump?
Yes—by design. The pump carries the easy days; gas steps in on the coldest ones and during certain defrost scenarios. Expect ~45–50% less furnace runtime, ~30% net utility savings on NG homes (house-dependent).
Why not Nest?
Poor commissioning tools and power-steal issues. We use Ecobee or the OEM communicating stat depending on the system.
