solar water heater operating at night

Does A Solar Water Heater Work At Night?

As more families look for sustainable options for their homes, solar technology has become very popular. In sunny climates, like our beautiful home in Oahu, solar water heaters are becoming highly sought-after. They’re a cost-effective solution to heating water and they’re environmentally friendly. What’s not to love?

That being said, people understandably have a lot of questions. How do solar water heaters work? Does a solar water heater work at night? Who can install them for us?

We are here to help answer all your questions. Keep reading below to learn about solar water heaters and if they work at night.

What is a Solar Water Heater?

To answer your question, it would be helpful to explain what a solar water heater is and how solar water heaters work. Solar water heaters are a method of heating water that uses sunshine as fuel. Since sunshine is free, solar water heaters are a cost-effective solution. The two main components of a solar water heater are the solar collectors, which intake the sunlight, and the storage tank. Solar water heaters can be either active or passive.

Active Solar Water Heaters

Active solar water heaters circulate water through the home using circulating pumps. There are two types of active solar water heater, including:

Direct Circulation Systems

Direct circulation solar water heaters heat your household’s water and move it around the home. This variety of solar water heaters are most common in Hawaii and other places with consistent sunshine.

Indirect Circulation Systems

These solar water heaters use a special heat transfer fluid that keeps the water from freezing and a heat exchanger. These types of solar water heaters are more common in cold climates that drop below freezing during the winter.

Passive Solar Water Heaters

Passive solar water heaters don’t utilize the same circulating pumps and controls that an active solar water heater would. They’re usually not as efficient as active solar water heaters, though they do cost less and may even last longer. There are two types of passive solar water heaters, including:

Integral collector-storage

Integral collector-storage passive solar water heaters work well in sunny climates.


Thermosyphon passive solar water heaters circulate water through the system based on temperature.

Does A Solar Water Heater Work At Night?

This is a great question. Your solar water heater collects solar energy during the day. If you choose the correct size and type of solar water heater for your situation, your solar water heater will usually generate enough hot water.

However, that’s not always the case. Most solar water heaters are installed with a backup unit. The backup unit is a standard water heater, utilizing gas or electricity to function. The backup water heater likely won’t be used all the time. It’s mostly to be used when you need hotter water than your solar water heater can provide. It can also kick on during times when you run out of hot water in the water collector. The backup water heater supplements the amount of water provided by the solar water heater and will rarely be used.

Should You Invest In A Solar Water Heater?

While the choice is up to you, a solar water heater can save money on your utility bills, especially when you live in a sunny climate like Hawaii. They’re a cost-effective and environmentally friendly way to heat your water while decreasing your energy use.

Get a Solar Water Heater with 535 Plumbing

535 Plumbing is a Hawaii Energy Participating Contractor. This means that our team follows strict standards and rules to provide high-quality, energy-efficient plumbing solutions. We analyze your home’s hot water usage, calculate your anticipated energy savings, offer a bid or cost estimate for a complete installation, deduct the Hawaii Energy Rebate ($1,250 on Oahu!) to give you a discount, and give inspections.

We are a family-owned and operated plumbing company that takes pride in going beyond the call. Our team is known for our impeccable customer service, meticulous handiwork, and reliable attention to detail. There are no hidden fees, no secrets, and no missed steps. Trust us to get the job done right, quickly, and properly! Call us to book your appointment today at (808) 300-0535.