Both get pitched as the answer to a cold Kiwi home, and they get compared constantly — sometimes by the same person. But they work in completely different ways, and for a lot of New Zealand homes the real answer isn't "either", it's "both". Here's how each one actually works, where each one wins, and why they're not always competing for the same job.
The short answer
Heat pumps are fast, affordable to install, and great at heating one room at a time. Underfloor heating is a whole-home system that heats every room evenly and quietly, with no cold spots or blowing air. If your floor is already coming up for a build or renovation, underfloor is usually the better long-term investment — and it can even be powered by a heat pump, so it's rarely a straight either/or choice.
How underfloor heating actually works
SunFlow® underfloor heating is a hydronic system — a closed loop of tubing is laid under your floor and warm water is circulated through it. The floor itself becomes a large, low-temperature radiator. Instead of heating the air and hoping it reaches you, the warmth radiates upward and heats every solid object in the room — walls, furniture, and you — the same way sunlight warms your skin before it warms the air around you.
Because the whole floor is the heat emitter, there are no vents, no visible units, and no draughts. It's also flexible on power source: gas, electricity, a wood boiler, a heat pump, or solar hot water can all drive the same underfloor loop, which is one of the reasons SunFlow® is the only heating system in New Zealand with a BRANZ Appraisal (No. 398).
How a heat pump works
A standard heat pump — the wall or ceiling unit most Kiwis mean when they say "heat pump" — works differently. It extracts latent heat from the outside air, compresses it to raise the temperature, and blows the warmed air into a single room through a fan unit. It's a convection system: it heats the air directly, and that warm air then heats everything else in the room as it circulates.
Comfort: why the two feel so different
This is where most people notice the difference immediately. A heat pump heats a room from one point, so warm air pools near the ceiling while the floor stays cooler, and the fan can be heard cycling on and off. Underfloor heating warms a room evenly from the ground up — no cold pockets, no draughts, and no moving parts to hear. It also doesn't stir up dust and allergens the way forced-air systems can, which matters if anyone in the house has asthma or allergies.
Underfloor heating
- Even heat, floor to ceiling
- Silent — no fan, no moving parts
- Heats the whole home, not one room
- No visible units or vents
- Best installed during a build or renovation
Heat pump (air-to-air)
- Fast to heat up a single room
- Lower upfront cost per room
- Simple retrofit, no floor access needed
- Warm air rises, floor stays cooler
- Runs a visible fan unit
Running costs and efficiency
Because radiant heat warms objects directly rather than warming air that then escapes and needs reheating, SunFlow® underfloor systems typically achieve energy savings of 20–40% over comparable forced-air heating, and thermostats can usually be set a couple of degrees lower for the same comfort level. A heat pump's efficiency is strong for the single room it's heating, but running several units to cover a whole house — or one large ducted unit — often costs more to install and run than a whole-home hydronic system designed for the job.
Actual running costs depend on your home's size, insulation, layout and chosen heat source, so treat any figure you read online — including the one above — as a guide, not a quote. The only way to get real numbers for your own home is a proper design consultation.
Can underfloor heating and a heat pump work together?
Often, yes — and this is the bit most comparisons skip. Because a SunFlow® underfloor system is hydronic, it needs a heat source to warm the water in the loop, and an air-to-water heat pump is one of the most efficient options available for that job. In practice, that means the "versus" framing can be the wrong question: the heat pump becomes the engine, and underfloor heating becomes the way that heat gets delivered evenly through the house, instead of blasted out of a single wall unit. Solar hot water can play a similar supporting role — see our guide to solar hot water heating for how that works alongside a heating system.
Which one suits your home?
- Building or fully renovating, floor's coming up anyway: whole-home underfloor heating is almost always worth the investment.
- Renovating a bathroom, kitchen or entryway only: under tile floor warming gives you the same comfort where it matters most, without touching the rest of the house.
- Existing home, floor's not coming up, need heat in one or two rooms: a heat pump, or a European-designed wall-mounted radiator running off the same hydronic principle, is the more practical retrofit.
- Whole-home comfort with the lowest long-term running cost: underfloor heating, ideally paired with a heat pump or solar as the heat source.
Frequently asked questions
Is underfloor heating cheaper to run than a heat pump?
For heating a whole house, underfloor heating is usually more efficient because it heats objects directly rather than air that constantly escapes. For heating a single room occasionally, a heat pump can be cheaper simply because you're only running one small unit. It comes down to how much of the house you actually need to heat.
Can I install underfloor heating in an existing home?
Yes, though it's simplest when floor coverings are already coming up for a renovation. Retrofitting into a home with no floor access underway is possible but adds cost and complexity — our team can advise what's realistic for your specific floor structure.
Do I need both a heat pump and underfloor heating?
No — they're not sold as a pair. But if you're already choosing underfloor heating, an air-to-water heat pump is one of several efficient options for the heat source that drives it, alongside gas, wood and solar.
How long does underfloor heating last?
SunFlow® in-floor components carry a 25 year limited warranty, with a 2 year warranty on above-floor equipment like thermostats and controls. Properly designed and installed hydronic systems are built to outlast most other home heating equipment.
Is underfloor heating worth it in a New Zealand climate?
For most of the country's damp, under-insulated housing stock, yes — even, draught-free heat also helps manage condensation and mould risk, not just comfort. It's most cost-effective when planned in at the build or major renovation stage.
Not sure which system fits your home? Our team can walk you through the options for your specific floor plan, budget and heat source — no obligation.
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