Do Heat Pump Water Heaters Produce Condensate?

Do Heat Pump Water Heaters Produce Condensate? Yes, heat pump water heaters do produce condensate as part of their normal operation. When warm, damp air is blown across the cold evaporator coils, some of the water vapour in the air condenses into liquid water – just like when you breathe onto a cold window and it fogs up. This condensate needs to be collected and drained away, so you need to consider where you’ll be able to fit the drain when you’re deciding where to put your new heat pump water heater.

Why does a heat pump water heater produce water?

An air source heat pump water heater takes heat from the air outside and transfers it into your hot water tank.

Air is blown across the evaporator by a fan – which has to be pretty quiet, or you’ll be told to turn it off at night! The evaporator itself is pretty chilly because the refrigerant inside it is absorbing heat from the incoming air.

When the air coming in is warmer than the evaporator surface, the moisture in the air starts to turn into water droplets – just as with a cold drink on a hot day or with an air-con system that’s cooling your house.

The water that forms is collected in a tray inside the machine before being directed out of the condensate outlet.

Our heat pump water heating range includes solutions for both compact domestic installations and larger commercial applications. For smaller requirements, see the 100 litre wall mounted hot water heat pump system.

For family homes, compare the 200 litre domestic hot water heat pump system and 300 litre domestic hot water heat pump system.

For larger buildings, consider the 400 litre commercial hot water heat pump system or 500 litre commercial hot water heat pump system.

How much condensate does a heat pump water heater produce?

To be honest, the amount of condensate produced is really variable – and can depend on loads of different things.

Like:

The temperature outside

How humid the air is

How long the heat pump has to run for

How much air is blowing across the evaporator

Exactly how cold the evaporator is

How much hot water you’re trying to heat

If you’re running the heat pump for a long time on a warm, damp day, it can produce a lot more condensate than if you were running it in a cool, dry place.

So it’s a good idea to design your drainage system to be able to handle a fair amount of water, rather than assuming it will only be small amounts.

Where does the condensate go?

Most heat pump water heaters have a dedicated condensate drain connection, which is usually a pipe that carries the water away to some place where it can do no harm.

Where possible, a gravity drain is the simplest and usually the best option – just make sure the pipe has a bit of fall to it and isn’t all kinked up where water can get stuck.

If gravity drainage isn’t an option, you might need a special pump, but only if the manufacturer says it’s okay.

What happens if the condensate drain gets blocked?

If the condensate drain is blocked, all sorts of problems can happen – like water leaking out of the machine or even triggering a fault.

Common causes of blocked condensate drains are dirt clogging the tray, blockages in the pipe, or just generally poor design.

If you notice water suddenly appearing out of the machine, it’s a good idea to check the condensate drain first – though it’s worth noting that water can also come from plumbing or safety drain pipes, so you need to figure out where the real problem is.

Can the condensate pipe freeze?

Yes, it can if it’s exposed to really cold temperatures – especially if the heat pump water heater is in a cold garage or outbuilding.

If the waste pipe freezes up, you can get a blockage that stops the machine from draining properly.

So, try to keep any external pipework in the cold a bit short and follow the manufacturer’s instructions for the job.

Is producing condensate the same as dehumidifying the room?

In a way, yes – when the heat pump is taking warm air in, it’s removing some of the moisture from it, so it can be seen as having a bit of a dehumidifying effect on the room.

This can be pretty useful in places like garages or outhouses, or other spaces that can get pretty damp.

But it’s worth remembering that this is not the main job of a heat pump water heater – it’s really just designed to heat water, so the amount of moisture it removes will depend on when it’s running and for how long.

Do ducted heat pump water heaters still produce condensate?

Yes, they still do – even if they’re ducted, and the air is coming from within the duct.

Moisture can still form on the evaporator coils whenever the machine is running.

Ducting just changes where the air comes from and where the cooled air is discharged – it doesn’t change the condensate production.

Does every installation need a condensate drain? Heat Pump Water Heater Condensate – Its Not Just About Disposing Of It The thought of heat pump water heater condensate is enough to give some people the heebie-jeebies – putting a reliable means in place to get rid of that water ought to be right up there alongside thinking about hot & cold water pipes, the electric hook up and airflow when you’re planning an installation.

Whilst a utility room, garage, or plant room might look like an ideal spot for a heat pump water heater, the availability of a suitable drain can make a huge difference to how smooth things are when it comes to installing the thing.

Condensate itself is a complete non-issue, not some kind of warning sign that the heat pump has a problem, just a normal result of the system extracting a bit of heat and moisture from the air. And with a proper drainage system in place, you shouldn’t have to be worrying about it at all.