I was delighted when Airbnb asked me to write for the Festival of Sustainability. Iโm pleased to write this post regarding a topic that has become important to me over the years: energy conservation.
Switching to an efficient electric hot water heat pump can be a great way to reduce your household energy bill. Although you may not need a new hot water system today, itโs worth doing a bit of research so that if yours breaks, youโre ready to replace it with a more efficient option.
How they work?
A hot water heat pump uses similar technology to a refrigerator or air conditioner, but in reverse. It uses heat energy in the air to heat water. Donโt ask me to explain the physics, but it works even during winter. Check out this explanation from the International Energy Agency if youโre interested in learning more.
What they cost?
A stove or air conditioner uses energy at a particular time, like when youโre cooking or when youโre home and itโs hot. But a hot water heat pump can use electricity when itโs free (if you have solar panels on your roof) or less expensive (if thereโs a time-of-day electricity rate where you live). It then stores hot water in a highly insulated tank until you or your guests need it.
Because electricity can be less expensive when thereโs a lot of it, not only can heating and storing hot water via solar power or an off-peak electricity rate help you save on hot water bills, it can also help the energy grid. Your hot water tank works like a battery, storing electricity in the form of hot water that can be used when energy grid demand is at its peak.
If youโre nervous about running out of hot water, consider paying a bit extra for a heat pump that has a quick reheat cycle. You can also get a larger tank to accommodate the number of people in your space.
Here in Australia, the price for hot water heat pumps can range from around $1,500 to more than $6,000 AUD (before government rebates).
Getting ready for a heat pump
Before your old hot water system breaks, think about how youโd replace it with a heat pump. There are some important considerations :
- Form factor: Heat pump hot water systems come with a tank and a compressor unit. They can be separate (where the compressor unit looks like the outdoor unit for an air conditioner) or combined (where the compressor is built onto the top of the tank). Either way, the compressor unit must be located outside or in a covered area that gets plenty of airflow. If you currently have an outdoor tank, an all-in-one system is the logical choice. If you have an indoor (gas or electric) one, consider where the compressor could go.
- Power point: If you currently have a gas system, youโll likely need a new dedicated power circuit. Be sure to check the specifications of the model youโre intending to purchase.
When youโre selecting a particular brand and model, there are again a few important considerations :
- The level of control: Can you control it using your phone or laptop to take advantage of off-peak power rates or your own solar generation?
- Energy efficiency: Take a look at the โCOPโ (coefficient of performance) rating and check how energy-efficient the system is. The higher the number, the more efficient, but the COP is measured at a particular ambient (outside) temperature.
- Operational temperature range: Make sure the unit is suitable for your winter extremes. Check the operating temperature range and ask the dealer how efficiency is affected by cold weather.
- Warranty: Check the type of warranty and what it covers, like labor and parts, and how long the warranty period is.
- Noise: Look for the decibel rating (dbA). The lower the number, the quieter it will run. Also consider where the unit will be located and if it will be close to a neighbor or bedroom window.
- Tank size: The recovery rateโhow fast water in the tank can be heatedโ determines what size tank you need for a given number of people. A higher-quality system might need half the tank size to do the same job as a lower-quality system.
- Refrigerant: Check the types of refrigerant gasses used and consider ones that reduce the environmental impact.
Chances are, youโll need to replace your hot water system quickly when it breaks. With a bit of research into which options best suit your needs, youโll be ready to upgrade to an energy-efficient electric heat pump.
