Common situation
A three-storey house that should only have one outdoor unit: how to heat, cool and run hot water
Cooling on every floor with as little outside as possible, mid-renovation — where the number of floors decides the answer.
Best fit for this home
Keep your existing heating and add concealed AC
Heating and hot water untouched; cooling delivered through ceiling grilles or cassettes rather than wall units
Strong fit. No close second, and nothing important left unknown.
This is the best fit because you're after better comfort throughout the home, you have a working boiler and overheating is the problem and you want to keep your existing heating.
- Keep
- your gas boiler · your radiators · your hot-water cylinder
- Add
- concealed units with 5 grilles · 2 outdoor units
- Remove
- Nothing
- Heating
- Your existing system stays primary; the concealed units can heat those rooms too
- Cooling
- Every room — from a loft, that reaches the top floor; the installer confirms how far
- Hot water
- Unchanged
- Radiators
- Stay, and stay your heating
- Indoors
- Ceiling grilles or cassettes, with the units hidden in a loft or ceiling void
- Outdoors
- 2 outdoor positions, subject to survey — usually one condenser serving the concealed units
- Work
- Significant: ceiling or loft access, duct routes and making good
Cost
££
A mid-range project: more equipment, more labour, more making good.
The air-conditioning part — 5 indoor units, 2 outdoor — estimates at £7,700–£18,100 installed.
Cost tiers are Airva's own assessment of these routes relative to each other, not a quotation. We don't publish a whole-home price range — an installer survey sets the price.
Why this won: Because the building is going to be open anyway, this does more of what you asked for than Keep heating + fixed AC.
- Improves comfort across the home, not one room
- Leaves a working boiler alone
- Keeps your heating and hot water exactly as they are
- Scales to cooling across the home
Every answer below is filled in. Change one and the plan updates.
The answers behind this plan
- Comfort throughout
- Gas boiler
- Radiators
- Cylinder on the boiler
- Keep the heating
- Cooling: every room
- Terraced
- 4 bed, 3+ floors
- Already renovating
- Prefers discreet
- Loft available
- Outside: garden or patio
- One outdoor unit preferred
- Permanent changes OK
- Mid-range project
The alternatives, and how they differ
Possible, not our first choice
Keep your existing heating and add fixed AC
- ↔ Less building work
- ↔ Costs less
Heating: your existing system stays primary; the room units heat those rooms efficiently on demand. Cooling: every room. Hot water: unchanged.
Read about this →Possible, not our first choice
Room units for now, while you plan the bigger change
- ↔ Less building work
- ↔ Costs less
Heating: unchanged. Cooling: every room. Hot water: unchanged.
Read about this →What would change this plan?
- If you were open to replacing everything → A heat pump with fan coils that heat and cool
- If you wanted to keep your radiators and replace the boiler → A heat pump on your radiators, plus fixed AC where you need cooling
Could a grant apply?
Not applicable to this plan. This plan keeps your existing main heating, so heating-replacement grants do not apply. Adding room cooling has never been grant-funded.
The eligibility rules, with the official sources →What an installer must confirm
- The age and condition of your boiler — this plan assumes it has years left
- How ducts would reach the floors below the loft, if at all
- A whole-home survey: heat loss room by room, pipe runs and equipment positions
Equipment in a loft serves the rooms beneath it. On a home with more than one floor that usually means the top floor, unless duct routes can be made through the building.
Heating-replacement grants don't apply to this plan, because your existing main heating stays. Adding cooling has never been grant-funded.
Generated by Airva's planner engine, version 2.0, from the answers above. An initial guide, not a technical system design or formal quotation. Cost tiers are Airva's own assessment of these routes relative to each other, not a quotation. We don't publish a whole-home price range — an installer survey sets the price.
Questions
A three-storey house that should only have one outdoor unit: what is the best system?
Keep your existing heating and add concealed AC. This is the best fit because you're after better comfort throughout the home, you have a working boiler and overheating is the problem and you want to keep your existing heating. It keeps your gas boiler, your radiators, your hot-water cylinder. It adds concealed units with 5 grilles, 2 outdoor units.
What would it cost?
A mid-range project: more equipment, more labour, more making good. The air-conditioning part of the plan estimates at £7,700–£18,100 installed. Cost tiers are Airva's own assessment of these routes relative to each other, not a quotation. We don't publish a whole-home price range — an installer survey sets the price.
What would change the recommendation?
If you were open to replacing everything, it would be a heat pump with fan coils that heat and cool. If you wanted to keep your radiators and replace the boiler, it would be a heat pump on your radiators, plus fixed ac where you need cooling.
Would a grant apply?
Not applicable to this plan. This plan keeps your existing main heating, so heating-replacement grants do not apply. Adding room cooling has never been grant-funded.