Heat pump questions — answered honestly

A heat pump doesn't generate heat — it moves it. Even when it feels cold outside, there's still heat energy in the air. The outdoor unit extracts this energy and transfers it inside, where the indoor unit distributes it through your room.

In summer, the process reverses: heat is extracted from inside your home and pushed outside, cooling the room. One unit handles both heating and cooling.

This is why heat pumps are far more efficient than electric heaters — you're moving heat rather than creating it from scratch, producing roughly 3–4 units of heat for every unit of electricity used.

Yes — modern heat pumps are designed to work efficiently down to around -15°C. Auckland's winters rarely drop below 5°C, which is well within the comfortable operating range. The damp, cool conditions we get in South Auckland are exactly the conditions heat pumps handle well.

The key is correct sizing. A properly sized unit will keep your home warm comfortably even on the coldest Auckland nights.

For most New Zealand homes, heat pumps are the most cost-effective heating option. They're significantly cheaper to run than electric panel heaters or fan heaters, provide both heating and cooling, and produce cleaner indoor air than combustion heaters.

Wood burners are cheaper to run if you have a free wood supply, but require more effort and produce indoor air quality issues. Gas heating is being phased out of new builds. For most households, a heat pump is the practical first choice.

A quality heat pump that's properly installed and regularly serviced should give 12–15 years of reliable service. Some last considerably longer. The factors that shorten lifespan are poor initial installation, blocked filters, and skipped servicing — all of which make the compressor work harder than it should.

No. Heat pump installation involves refrigerant handling (which requires a licensed refrigeration engineer), electrical connections (which must be carried out by a registered electrician), and building work. DIY installation is illegal, will void your manufacturer warranty, and may also void your house insurance. It also risks a gas leak or electrical fault that could be dangerous.

Most single room installations are completed in 3–4 hours. Multi-room systems take 1–2 days. Ducted whole-home systems typically take 2–4 days depending on home size and duct complexity. We complete everything in one visit where possible, including commissioning and a full system test before we leave.

The indoor unit should be on an interior wall where possible, away from direct sunlight and positioned for good air distribution across the room. The outdoor unit needs good airflow clearance, protection from prevailing winds, and a solid mounting surface. We assess the best placement for both units during the site visit — placement significantly affects performance and longevity.

Most installations require a dedicated electrical circuit. In newer homes this is usually straightforward. Some older South Auckland homes may need minor electrical upgrades — we identify this during the site assessment and factor it into your quote so there are no surprises on installation day.

Some — there's drilling involved for the refrigerant line penetration through the wall, and some dust from that. We use drop sheets to protect flooring and furniture, and clean up completely before leaving. Most people are surprised by how tidy the job is.

We can install units supplied by the customer in some circumstances, but we strongly recommend buying through us. When we supply the unit, we're responsible for the whole job — unit quality, installation, and warranty. If you supply your own unit, our liability is limited to the installation only. Call us and we'll discuss your specific situation.

We commission the system — vacuum out the refrigerant lines, charge with refrigerant, check pressures, and run the unit through heating and cooling modes. We then walk you through the controls, explain how to clean the filters, and register the manufacturer warranty. You should plan your first annual service for 12 months after installation.

Roughly 3–4 times cheaper for the same amount of heat output. An electric heater converts one unit of electricity into one unit of heat. A heat pump uses one unit of electricity to move 3–4 units of heat from outside to inside. This efficiency ratio is why running costs are so much lower.

The actual saving depends on what you're replacing, your electricity rate, and how you use the unit — but the efficiency advantage is consistent regardless of brand or model.

For most homes, it's more efficient to leave it on a low setting all day rather than turn it off and reheat from cold each evening. It takes significantly more energy to raise a cold room from 10°C to 20°C than to maintain a room at 16°C throughout the day.

The exception is if the room is very well insulated and you're away for more than 8–10 hours — in that case, turning it off may be worthwhile. WiFi-enabled models let you turn the heating on remotely before you arrive home, which is the best of both options.

18–20°C for general living areas is both comfortable and efficient. Every degree above 20°C increases running costs noticeably. For bedrooms overnight, 16–18°C is typically sufficient — cooler temperatures support better sleep and cost less to maintain.

Avoid setting it to the maximum and expecting it to heat faster — heat pumps don't work like a fan heater. They reach their set temperature gradually and maintain it.

Yes — the same unit that heats in winter cools in summer. You switch it to cooling mode on the remote and it runs in reverse, extracting heat from inside your home and pushing it outside. This is far more effective than a portable air conditioner and significantly more efficient.

A single high wall or floor mounted unit will heat the room it's installed in well. Heat doesn't travel around corners or through closed doors effectively, so a single unit won't heat an entire house. For whole-home heating, you need either a multi-room system (individual units in each room from one outdoor unit) or a ducted system that delivers conditioned air throughout the home via ceiling ducts.

Up to $3,450 for eligible homeowners. Community Services Card and SuperGold Combo Card holders receive an 80% subsidy (maximum $3,450). Other eligible homeowners receive a 66% subsidy (same maximum). The maximum figure applies to the full cost of the heat pump and installation combined.

See our full subsidy page for complete eligibility details.

You must own and live in the home as your primary residence, the home must have been built before 2008, and it must not already have a fixed heater in the living area. You also need to hold a Community Services Card or SuperGold Combo Card, or live in an area identified as highest-need by EECA.

The heating grant is targeted at highest-need households — middle-income areas without a qualifying card may only be eligible for insulation grants, not the heat pump grant. Call us and we'll check your address against the EECA system in a few minutes.

No — as an EECA-approved provider, we handle the entire application. We complete the paperwork, submit it to EECA, and deduct the subsidy from your invoice directly. You pay only your share. You don't fill in a single government form.

Yes — homes must have ceiling and underfloor insulation to EECA standards to qualify for the heating grant. If your home lacks insulation, the good news is that insulation is also funded under Warmer Kiwi Homes. We can assess and arrange both as part of the same application process.

No — the Warmer Kiwi Homes subsidy is for owner-occupiers only. Rental properties are excluded. However, landlords are legally required to meet Healthy Homes Standards heating requirements, which include a fixed heater capable of heating the main living area to 18°C. We install heat pumps for rental properties at standard rates.

Too small and the unit runs constantly at full capacity trying to reach the set temperature — it may never get there on very cold days, and it wears out faster. Too large and it reaches temperature quickly then cycles on and off repeatedly. Short-cycling prevents proper dehumidification, makes the room feel clammy, and is also harder on the compressor. Correct sizing matters.

No — room size is a starting point, not a formula. Ceiling height, insulation quality, number and size of windows, room orientation, and what's above and below the room (garage, roof space, heated room) all affect the required capacity. Two 25m² rooms in the same house can need different sized units depending on these factors. We calculate the correct size during your site assessment.

The sizing calculator gives a useful ballpark figure based on room dimensions — good for initial planning and budget estimates. For an accurate quote and correct specification, we need to do a site visit to assess insulation, windows, orientation, and electrical setup. The site visit is free and takes 20–30 minutes.

Yes — poor insulation means heat escapes quickly, which means the unit needs more capacity to maintain temperature. In some cases it makes more sense to improve the insulation first and then install a correctly-sized heat pump, rather than installing an oversized unit to compensate for the heat loss. We advise on this during the assessment. If your home qualifies for the Warmer Kiwi Homes subsidy, insulation funding may be available alongside the heating grant.

Every 1–3 months during periods of heavy use. The filters slide out easily — rinse under a tap, let them dry fully, and replace. Clogged filters restrict airflow, reduce efficiency noticeably, and degrade air quality. It takes about three minutes and makes a real difference. We show you how during installation.

A proper annual service covers both units. Indoor unit: deep clean of coils and internal surfaces, mould removal from fan blades, filter clean, condensate drain flush, and performance test. Outdoor unit: coil pressure clean, debris removal, electrical terminal inspection, refrigerant pressure check, and performance verification. We provide a written condition report noting anything that needs attention.

Yes — dirty coils are the single biggest cause of reduced heat pump efficiency. A well-maintained heat pump uses significantly less electricity for the same output compared to a neglected one. Annual servicing also keeps the warranty valid for most manufacturers and catches small issues before they become expensive repairs.

Yes — we service and repair all major brands regardless of who installed them. Your heat pump doesn't care who put it in; it just needs proper maintenance to keep running efficiently.

You can clean your filters yourself — that's encouraged and easy. The coils themselves require specialist equipment. Standard garden-hose pressure can bend or damage the delicate aluminium fins on the coils, and household cleaning products can corrode them. We use purpose-built pressure cleaning equipment specifically designed for heat pump coils. See our cleaning page for more detail.

Light frost on the outdoor unit in cold weather is completely normal. Modern heat pumps have an automatic defrost cycle that periodically reverses operation for a few minutes to melt the frost. You may hear the unit working differently and see steam — this is normal. If the outdoor unit is completely blocked in thick ice that isn't clearing, that indicates a refrigerant issue, a defrost sensor fault, or insufficient airflow — call us.

The most common cause is a blocked condensate drain. Heat pumps produce condensation during operation which is normally drained away through a pipe. When the drain is blocked, water backs up and drips from the indoor unit. A service and clean usually resolves this. If the dripping is severe or ongoing, call us — water inside walls or ceilings can cause damage.

Mould or bacteria growing on the internal surfaces of the indoor unit — typically on the fan blades or evaporator coil. This is common and fixable. A professional deep clean removes the source of the smell entirely. Running the unit in fan-only mode for 20–30 minutes after heating or cooling helps prevent moisture buildup, which reduces the likelihood of mould forming.

The unit stops working — heat pumps require electricity to operate. When power is restored, most units restart automatically at their last settings. There's no damage from a normal power interruption.

In order: check the batteries (this is the cause more often than you'd think), check that nothing is blocking the infrared sensor on the indoor unit, and check that the unit is receiving power at the circuit breaker. If none of these resolve it, the receiver in the indoor unit or the remote itself may have failed — call us.

Both do the same job — the difference is placement. A high wall unit mounts on the wall at height and distributes air downward. A floor mounted unit sits low on the wall and pushes warm air upward. Floor mounted units are used when wall space is limited — lots of windows, built-in wardrobes, or low ceilings — or where accessibility is a consideration. Performance is equivalent.

Generally when you need heating in three or more rooms. A multi-room system uses one outdoor unit connected to multiple indoor units — more efficient than separate standalone units, only one outdoor unit on your exterior wall, and the individual rooms remain independently controllable. For 1–2 rooms, standalone units are simpler and more cost-effective.

For new builds or major renovations where ceiling access is open, ducted systems offer genuine advantages — no visible indoor units, even temperature throughout the home, and good property value. For existing homes being retrofitted, the additional complexity and cost is harder to justify unless aesthetics are a priority or the ceiling cavity is easily accessible. We'll give you an honest comparison for your specific home. See our ducted systems page for more detail.

Most modern models from Mitsubishi Electric, Daikin, and Panasonic support WiFi connectivity — either built-in or via an optional adaptor. This allows smartphone control, scheduling, and in some models integration with voice assistants. See our WiFi control page for detail on which models support this and how it works.