Plumbing – Are You Getting Hot Water?

One of those things I have never got quite right is hot water plumbing.

This means running the taps for a while to get hot water.

In the morning I switch the shower hot water on and can have a shave before the shower is ready to jump in.

Some Suggestions

The key thing is to get the hot water service close to the taps, or showers that are going to be used the most.

The usual site for the hot water service is outside the laundry.

That made sense when people used lots of hot water in the washing machine.

Now with cold wash detergents it’s probably the showers that use the most hot water, especially if you have teenagers who want to spend half an hour in the shower.

The more you can group bathrooms and the kitchen the sooner you will get hot water, and the less water that will be wasted.

If you can’t do this and you have a big house perhaps two separate hot water services or several small instantaneous hot water heaters may be the way to go.

Not Easy

In the last house I built I thought I had got it reasonably correct.

The laundry, 2nd bathroom and the kitchen are reasonably close to the centre of the house as is the hot water service.

What I hadn’t allowed for is that the kitchen sink is in an island unit.

The pipe run the plumber chose was up into the roof, past the island unit to the wall, down the wall, under the floor, and then back up to the sink. That’s about three times the amount of pipe than if the run had been direct under the floor to the sink.

It uses more cold water to get to the hot water through to the kitchen sink than our ensuite, which is further from the hot water service.

I suppose I should have discussed the actual pipe runs prior to signing the final contract!


For similar posts see Plumbing


Safe Hot Water

Did you know that around 90 Australian children are admitted to hospital each year due to scalds from the water from the tap, with many will requiring skin grafts.

Disabled and the elderly are also more at risk of scalding injury.

The water doesn’t have to be boiling!

Water at a temperature of 65 degrees C will cause full thickness burns in 1 second, even at 60 degrees it only takes 5 seconds.

Those boiling water taps (pictured) for making tea are particularly dangerous

Solar hot water systems can be a problem particularly  in summer

They can heat water up to much higher temperatures than the normal maximum of 65 degrees for gas or electric hot water systems.

Making it Safe

If you have a gas or electric system set the maximum temperature to 50 degrees C. If you are not sure on how to do this get a plumber to make the adjustment.

This will not only improve safety but save you money as the system won’t loose heat as fast.

If you have a solar hot water system make sure the tempering valve is fitted and set it at 50 degrees which will automatically mix cold water with the hot water if the hot water is above the preset temperature.

If you ‘must’ have a boiling water tap do set it right at the back of the counter where tiny fingers can’t reach!


For similar posts see Plumbing


Solar Hot Water

With the current emphasis on building efficiency solar hot water systems are pretty much a standard option if not automatically included.

These systems incorporate either gas or electricity boosting for cloudy days.

Here are a few thoughts on the options for solar hot water:

Split System or Tank On Roof

  • Systems with Tanks on the roof are the most efficient . They don’t need a circulation pump to circulate the hot water to the storage tank and don’t have long pipe runs that lose part of the heat you have collected. If this is the way you decide to go make sure your roof has been designed to take the load.
  • Split systems are easier to service when they go wrong as everything other than the panels is at ground level. Many people also prefer the look as they don’t like the large tank on the roof for aesthetic reasons.

Flat plate or Evacuated Tube Panel

  • Evacuated tube systems are more effective. Also from comments on forums I hear 2mm evacuated tubes are stronger than flat plate collectors in the case of large hail, and are less likely to be hit square-on, due to their shape. Just make sure you aren’t getting cheap quality thinner walled tubes.
  • Modern good quality evacuated tube and flat plate systems should be essentially maintenance-free. Just make sure of the quality, it can cost $300-$400 in labour to replace a defective panel even if the actual panel is replaced under warranty.


Some of the early Solar water systems only insulated the hot water coming from the system. This is poor practice as once the system starts running the water from the storage tank back to the panels warms up. If this cools in the pipes to the panels you will be loosing efficiency. Make sure you have all pipes insulated.

Boosting Systems

  • I think Gas Boosting is probably the best way to go even if you have the higher priced bottle gas rather than mains gas. This is because gas systems only boost the water when you want it rather than electricity where you are heating the whole tank up even if you are only using 10% of the contents.
  • If you `go for electricity its best go for an off peak boosting, but only switch it on if the forecast is for cloudy weather.


See why a West Roof Mounting may be worth thinking about

For more  information on choosing systems for your new house see  ‘Selection / Pre-Start Guide’