Monobloc or Split? Picking a Heat Pump Type for a Leicester Terrace or Semi
Last reviewed: 2 October 2026
Two types of air-to-water heat pump, explained simply, with practical advice on which suits a Leicester terrace with a narrow yard, a semi with a garden, a flat, or a home with a cellar.
Two types, simply put
- Monobloc: one box outside does everything. Hot water comes into the house through pipes. This is what most UK homes get.
- Split: a smaller box outside, plus a second unit indoors. They’re joined by refrigerant pipes, and the indoor unit heats your water.
Both connect to radiators and a hot water cylinder, and both qualify for the £7,500 grant.
Why most Leicester homes get a monobloc
- Simpler to fit. The refrigerant is sealed at the factory, so installers don’t need to work on it in your home.
- Usually cheaper.
- Nothing extra indoors apart from the cylinder and controls, which matters in a terrace where cupboard space is tight.
The downsides: the outdoor box is bigger, and the water pipes running outside need protecting from frost, usually with special valves or antifreeze in the system. Leicester gets regular frosty nights, so ask your installer how they’ll do it.
When a split might be better
- A very narrow back yard. The smaller outdoor unit of a split can be easier to fit and to keep quiet enough for the neighbours. The noise must be 37 dB(A) or less at the nearest neighbouring window to avoid needing planning permission.
- The best spot is a long way from the house. Refrigerant pipes can run further than outdoor water pipes without losing much heat.
- A flat, where the freeholder may prefer a small outdoor unit.
- A dry cellar that could house the indoor unit and cylinder, freeing up space upstairs.
Splits need an engineer with F-Gas certification to connect the refrigerant pipes, and they usually cost a bit more.
Moving from storage heaters?
Either type works, but you’ll need radiators and pipework installed too. If you live in a small flat and don’t want radiators fitted, an air-to-air heat pump — which blows warm air like a reversible air conditioner — is a different option. It earns a £2,500 grant but doesn’t heat water.
Quick guide
| Your home | Usually best |
|---|---|
| Interwar or post-war semi with a garden | Monobloc |
| Victorian terrace with a reasonable yard | Monobloc |
| Terrace with a very narrow yard close to neighbours | Consider a split |
| Flat | Split, or air-to-air for small flats |
| Best outdoor spot far from the house | Consider a split |
Ask your installer
- Which type do you recommend for my home, and why?
- How will you protect outdoor pipes from frost?
- Where will any indoor unit and the cylinder go?
- Does the noise calculation pass with the unit you’ve chosen?
Related: what’s an air source heat pump? · planning permission in Leicester
See what a heat pump would look like in your Leicester home
The mechanism is the same in every UK home; the design is specific to yours. Our team carries out a free in-home survey including a full room-by-room heat-loss calculation, identifies the system size and configuration that fits your property, and provides a written quote with the £7,500 BUS grant already deducted.
You'll see the actual figure you'd pay — not an estimate — and the projected efficiency for your specific install.