Energy Source Gas Electric Solar Heat Pump

Water heating uses a lot of energy. It is actually about a 1/3 of the total energy used.

Energy costs are not cheap, and on going. Hence a lot of interest in heating water from

some other cheaper source. In the past there has been a lot of interest in home made solar for instance.

To save money some home owners turn off their water heaters until they need hot water to reduce heating costs.

The current trend is toward heat pump water heaters away from gas to avoid line charges.

Selection Process

Heat pump water heaters are cheap to run but expensive to install. Low in CO2.

Gas water heaters next cheapest to run and not too expensive to install. But there is a line charge.

Big advantage is lots of hot water. Some gas instantaneous water heaters are endless hot water.

Standard electric immersion water heaters. Cheap to install expensive to run. If you have Solar PV you can use the power to heat the hot water when you have no battery.

Solar – Expensive to install but some installations are free to heat the water for most of the year.

Ground Source – high capital cost. Cheap running costs.

Should low CO2 be a factor in selecting hot water heating
New Zealand is a low CO2 country in terms of renewable energy at about 80%. So a lot of electric energy is low CO2.

How ever for every new electric water heaters or space heaters installed uses the power topped up with electricity generated by coal.

Coal has a very high particulates and CO2 output. Higher than gas.

So dont remove gas thinking your are reducing CO2 output. You are using coal.

Until New Zealand gets a lot more Carbon free power we will be using coal to make it.

The lowest CO2 would be heat pump or solar.