Can You Install a Heat Pump in an Old House? (2026 Guide)
A hundred-year-old villa in Palmerston North holds a huge amount of character and not much insulation. Ask whether you can fit a heat pump into one and the honest answer is yes, but not quite the same way as in a 2020s build. The walls, the wiring and the room itself all behave differently, and skipping that step is exactly why some older-home installs end up undersized and expensive to run. Here’s what changes when we heat a villa, bungalow or old state house instead of a new build.
Request A free Quote Today!
Yes, You Can, But the Room Changes the Answer
A heat pump goes into an old house just as reliably as a new one. We install into villas, bungalows and 1960s state houses across Palmerston North every month. What changes is the planning that happens before the unit goes on the wall. An uninsulated villa with single glazing and high studs loses heat far faster than a code-built home from the last ten years, so the same size room in each needs a different capacity, and often a different wall for the indoor unit altogether.
Sizing for a Draughty, High-Stud Room
Our default sizing formula is room volume in cubic metres multiplied by 55 watts for a reasonably insulated home. For an uninsulated villa with single glazing, we push that closer to 65 watts per cubic metre, because the walls, the underfloor gap and the high ceilings ask more of the unit before it’s even fighting the cold outside. A lounge that would need a 4kW unit in a new build often wants the next size up in a villa, closer to 5 to 6kW, once we’ve walked through insulation, window area and ceiling height at the free assessment.
Why the Switchboard Gets Checked Before the Wall Does
An older switchboard is one of the first things we look at, not the last. Homes wired in the 1960s or earlier sometimes still run fuses instead of circuit breakers, or don’t have spare capacity for a heat pump circuit without an upgrade. Our own registered electricians check this at the free assessment, because finding out on install day means a delayed job and a second visit. Every heat pump we connect gets wired and certified by our own team either way, with a Certificate of Compliance issued on completion, but an older switchboard is the one variable that can add real cost to an otherwise standard install.
Where the Units Go on a Villa or Bungalow
No back wall. No easy pipe run. No drama.
Plenty of Palmerston North villas and bungalows don’t have a straightforward external wall in the right spot. Board and batten construction, a veranda blocking the ideal position, or a lounge with no exterior wall at all because it sits in the middle of the house. None of that rules a heat pump out, it just changes the plan. We run longer pipe runs in colour-matched trunking rather than leaving pipework exposed across weatherboards, fit a condensate pump where gravity drainage won’t work, and position the outdoor unit for airflow, frost drainage and your neighbour’s sleep rather than wherever is easiest to reach. Where a high wall position genuinely doesn’t work, we’ve covered the floor console alternative in more detail, and it solves more villa installs than people expect.
Heating a Villa You Can’t Easily Insulate
We don’t install insulation or double glazing, and we won’t pretend a heat pump replaces either. What we can do is size around what you’ve got. If your underfloor and ceiling insulation are already in reasonable order, a correctly sized heat pump keeps a villa warm through a Manawatū winter without much drama. If the house is still largely uninsulated, the heat pump works harder and costs more to run than the same unit in an insulated home, and we’ll say that honestly at the assessment rather than promising a number we can’t back up. Older villas are also more prone to damp and condensation than newer builds, and pairing the heat pump with home ventilation tackles the moisture a heater alone won’t fix.
What It Costs Compared With a Modern Home
A straightforward villa install with a sound switchboard and an easy external wall costs the same as any other back-to-back job: $1,750 to $2,000 for a bedroom-sized unit, $2,250 to $2,500 for a living area. What changes the number in an older home is everything around the unit rather than the unit itself, a switchboard upgrade, a longer pipe run in trunking, a condensate pump, or a floor console where a high wall position won’t work. None of that gets guessed at. We quote it as a fixed, itemised price after the free site assessment, so you know the real number before we start rather than after.
Heat Pumps in Old Houses FAQs
Can You Put a Heat Pump in a Villa or Old House?
Yes. Structurally it’s no different to a new build, timber-framed villas take a heat pump easily. What changes is sizing for less insulation, checking the switchboard, and finding the right wall or a floor console where a straightforward position doesn’t exist.
Do I Need a Bigger Heat Pump for an Older Home?
Often, yes. We size older, less-insulated homes closer to 65 watts per cubic metre rather than the 55 watts we use for a well-insulated modern room, so a lounge that would take a 4kW unit new might need 5 to 6kW in a draughty villa.
Will My Old Switchboard Need Upgrading?
Sometimes. Homes wired before circuit breakers became standard occasionally need switchboard work to safely take a heat pump circuit. We check this at the free assessment and quote it upfront if it’s needed, rather than finding out on install day.
Should I Insulate Before Installing a Heat Pump?
If you can, yes. We don’t install insulation ourselves, but a heat pump in an insulated villa costs noticeably less to run than the same unit fighting an uninsulated one, so ceiling insulation especially is worth doing first if your budget allows it.
What If There’s No Good Wall for a High Wall Unit?
It’s common in villas with verandas, board and batten cladding or no clear exterior wall in the room that needs heating. We route pipework in colour-matched trunking, use a condensate pump where needed, or fit a floor console instead, whichever suits the room without compromising the look of the house.
Verdict on Heat Pumps in Old Houses
An old house is not a reason to skip a heat pump, it’s a reason to plan the install properly. Get the sizing right for the insulation you have, check the switchboard before install day rather than during it, and choose the wall position, or the floor console alternative, that suits the room instead of whatever’s easiest. Do that and a villa or bungalow heats just as well as a new build, usually for a similar installed price. If you’re weighing up an older Palmerston North home, our free site assessment covers the insulation, the wiring and the room itself, and you get one fixed number rather than a guess.