Solar water heater, heat pump or gas boiler?
All three give you the same result — hot water — but they get there in completely different ways, and each one has its own installation requirements. The right choice is not the one that is "best" in the abstract, it is the one whose requirements your place actually meets.
The table below compares how each one heats and what it needs on site, with no consumption figures or prices — those depend on a site visit, and any number written here without seeing your home would be a guess.
| Comparison | Solar water heater | Heat pump | Gas boiler |
|---|---|---|---|
| What heats the water | Roof collectors absorb the sun’s heat and pass it to the water in an insulated tank | A unit draws the heat already present in the outside air and moves it into the water — it moves heat rather than generating it | A gas burner heats the water as it flows, the moment you open the tap |
| What it depends on | Mainly the sun, with an electric backup element for overcast days | Electricity — but completely independent of sunshine | Gas — mains or cylinder, depending on what is available on site |
| When it works | Heats during the day, and the insulated tank holds that heat into the evening and morning | Day and night, all year round, regardless of whether it is sunny or overcast | The moment you open the tap — no waiting and no tank to run out |
| What it needs on site | Enough unshaded roof area for the collectors and tank, with direct sun reaching them | Space for an outdoor unit with free air around it — no sunny roof required | A gas connection and ventilation that meets the regulations |
| The tank | Central to the system — it is what makes daytime heat available at night | A tank kept hot by the pump and ready when you need it | Instant types work with no tank; central systems use one |
| Shape of the running cost | The sunshine itself is free; consumption is concentrated in the backup element on overcast days | Continuous electricity use, with the pump moving existing heat instead of generating it with an element | Follows the price of gas and how much hot water you use |
This table deliberately carries no savings percentages or prices: the real figure changes with the number of people, the draw-off points, the roof and the fuel available to you — so it is settled during a site visit, not on a page.
Choose this one if…
- Solar water heater
You have an unshaded roof with enough area, and you want the largest possible share of your water heating to come without fuel — with the backup element covering overcast days.
- Heat pump
There is no suitable roof, or not enough sun reaches it, and you want heating that runs day and night without depending on the weather or on a gas connection.
- Gas boiler
You want hot water the instant you open the tap and you have a gas connection — or you need hot water and central heating from the same appliance.
Questions people ask before choosing
Which one is cheaper to run in the long term?
There is no single answer that fits every home, and anyone who gives you a savings percentage without seeing your place is guessing. What decides it for you is: how many people use hot water and at what times, what the roof looks like and whether sun reaches it unshaded, and which fuel is available including whether there is a gas connection. A site visit is what produces that figure for your specific home.
Can I install a solar heater if the roof is not in full sun all day?
A solar heater works in proportion to the direct sun that reaches it, so shade falling on the collectors reduces what it heats and makes the backup element run more often. If the roof is shaded by a neighbouring building or by tanks, or there is not enough clear area, a heat pump is usually the better fit because it does not need sun at all. A site visit settles this before you buy.
Does a heat pump work in winter?
Yes, because it draws the heat already present in the outside air rather than relying on sunshine, so it keeps working at night and on overcast days. What is normal is that its efficiency falls as the air gets colder, because there is less heat in the air for it to draw on. Sizing it correctly for your local conditions is done during the site visit.
Can I combine more than one system?
Yes, and it is common in practice. The usual arrangement is a solar heater as the main source with a backup behind it — an electric element or a gas boiler — that runs on days when there is not enough sun or when demand is high. That way you get the most out of the sunshine without ever waiting for water to heat up.
What decides the choice in the end?
Four practical things: the number of people and hot-water draw-off points in the home, the roof area and how much sun reaches it, the fuel available to you and whether there is a gas connection, and whether you need instant hot water or a tank that covers your usage periods. Tell us those on a call and we will name the technology and the capacity without guessing.
Not sure which one suits your home?
Tell us how many people live there, what the roof looks like and which fuel you have, and we will tell you the right technology and capacity — the call costs you nothing.