Single point or multipoint water heater: which one your house needs
A single point heater sits on the wall at one shower and heats water for that shower only. A multipoint heater sits in one place and sends hot water to several outlets. The heater makers compare the boxes. The bigger difference is in your pipes.
Choosing between them decides how much plumbing the job needs, so it is worth settling before anyone buys a unit. If you already know which one you want, our water heater installation and repair page covers how we fit it.
What each one is
Single point
Mounted at the outlet it serves, nearly always the shower. Cold water goes in, warm water comes out of that one head. Every other tap in the house stays cold. This is the heater most Filipino bathrooms have, because most households only want hot water for bathing.
Multipoint
Mounted in one central place, often under a sink or just outside a bathroom, and piped to several outlets: a shower, a basin, sometimes the kitchen sink. Each outlet gets a mixer valve to blend the hot with the cold.
What the choice does to your plumbing
A single point heater uses the cold line that already reaches your shower. The plumbing work is short: a connection at the inlet, one at the outlet, and a valve so the unit can be isolated later.
A multipoint heater needs a hot water line from the unit to every outlet it serves. In a house built without hot water lines, which is most houses here, that line has to be run new. In concrete and hollow block walls that means either chasing a channel into the wall and plastering over it, or running the pipe on the surface. It is the larger part of the job, and it is the part the heater brochures leave out.
The hot line also has to be a pipe made for heat. PPR is rated for hot water at around 80 degrees Celsius. Plain PVC is a cold water pipe. Our guide to PPR and PVC pipe explains which goes where.
Water pressure decides more than the brochure does
Drag the drawing sideways to see all of it.
An instant heater only fires when enough water flows through it to close a switch inside. One maker puts the minimum at about 2 litres a minute or 3 psi. Below that the heater looks dead while being in working order, which is the commonest fault on our no hot water guide.
A multipoint heater has the harder job. When two outlets run at once the flow splits between them, and in a house fed by a low tank or a tired pump there may not be enough for both. If your shower is already weak, fix the low water pressure before choosing a heater, or a multipoint will disappoint you.
The electrical side is not ours
Drag the drawing sideways to see all of it.
Both types draw a heavy current. The same maker asks for a 20 amp circuit for an instant heater, and most units carry their own earth leakage breaker. The circuit, the breaker and the earth belong to an electrician. Book one alongside us, and do not run a heater off an extension lead.
Which one to choose
- One bathroom, and you only want hot water in the shower: a single point heater. Least plumbing, simplest to service.
- Two bathrooms far apart: two single point heaters are often simpler than one long hot line, because water sitting in a long pipe goes cold and runs out first every time.
- Several outlets close together, hot water wanted at a basin or the kitchen sink too, and good pressure: a multipoint heater can make sense.
- Weak pressure at the shower today: fix that first, whichever heater you pick.
Questions about choosing a water heater
- Can one single point heater serve two showers?
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No. A single point heater is fitted at one shower and heats the water for that outlet only. A second bathroom needs its own unit, or a multipoint heater with a hot line run to both.
- Will a multipoint heater work in a house with weak water pressure?
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Only for one tap at a time, and sometimes not even that. An instant heater does not fire until enough water moves through it, and a multipoint serving two outlets at once needs more flow again. Sort the pressure out first, then choose the heater.
- Can the hot line be ordinary PVC pipe?
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It should not be. PVC is made for cold water and drainage. PPR is rated for hot water at around 80 degrees Celsius, which is why it is the usual pipe for a hot line from a heater.
- Do you wire the heater as well?
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No. The circuit, the breaker and the earth are an electrician's work. We fit the heater to the water supply, run any hot lines and check the flow through it before it goes on the wall.
- Is a shower heater the same as a water heater?
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Here, yes. A shower heater is the single point unit on the wall of the shower, and it is a water heater that serves one outlet. A multipoint unit is also a water heater, serving several. The brochures say water heater; the hardware shop and most householders say shower heater for the single point kind.
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