The Difference Between Tankless Hot Water Heaters & Solar Water Heating

Hot water heater units are a staple domestic appliance around the country. It is impossible to imagine living in a home where there is no consistent supply of hot water for showers and other functions. Water heaters came into existence in the late 1900’s when Norwegian mechanical engineer Edwin Rudd developed the first automatic storage-type gas-fuelled hot water heater. Since then, the humble water heater has undergone major advancements, which resulted in the modern heating appliance we all know today.

Most households across the US, Europe, and Asia use storage-type water heaters. It typically consists of a cylindrical container used for storing heated water. The common household heater size has a capacity of 75 to 400 liters. In most areas around the country, natural gas piped through municipal lines is the most common fuel source for water heaters. However, other fuel sources such as electricity, propane, oil, and solar power are also available.

Storage-type water heaters are reliable in terms of technology and function. This is one reason why a lot of homes still have them installed. In recent years, much emphasis has been given to using tankless water heaters. Instead of bulky storage tanks, an instantaneous hot water heater saves precious space and only heats water on demand. This innovation also improves the energy efficiency of earlier hot water heater models.

A Focus On Tankless Hot Water Heater

If you are used to waiting around 20 minutes for hot water to run in your shower, you will appreciate the speed at which an instant hot water system provides hot water at the point of use. By heating water only on demand, you are saving energy wasted when water is consistently heated while in storage. Many homes in the Pacific Northwest have begun to consider switching to a tankless hot water system. In fact, instantaneous heating systems are common across European countries. But switching from conventional tank-type water heating to instantaneous water heating is a major decision. Before you decide whether your home is a good candidate for a switch, it is also important to understand how a tankless water heater works and the factors to consider before making a change.

One of the biggest pitfalls of using a tank-type water heater is the heat loss. While water is in storage, the system will continuously heat the stored water. The amount of energy used to keep stored water hot leads to a lot of energy lost. An instant hot water heater resolves much of the problem with energy loss by heating water only when you request it at the point of use.

An instant hot water heater uses a heat exchanger to raise water temperature. It works by transferring heat generated from a source such as an electric coal or gas burner into the water. When you turn on a tap, water passing through the pipes will circulate through the heat exchanger to heat it according to your desired temperature. There are two types of instant hot water systems:

  • Whole house heating system
  • Point-of-use heaters

Point-of-use heaters are usually installed in kitchen sinks and underneath cabinets to produce small amounts of hot water needed for specific chores such as washing dishes. Point-of-use heaters benefit large households with higher hot water demand, which a single instant hot water system can support.

Whole house systems are typically powered by either natural gas or electricity. In instances when water pressure drops because of high hot water demand, you can install several instant water heaters in different areas of the home in parallel connection to the water and heating source.

Choosing The Tankless Hot Water Heater For Your Home

There are two things you should consider when choosing a tankless water heating system for your home:

  • The flow rate or the amount of heated water needed at any time.
  • The rise in temperature or the temperature difference between the groundwater and desired temperature output.

You can request a qualified technician to help you calculate the temperature rise and flow rate required for your home. Once you have this information, you will know what type of hot water heater works best for your household needs. While it is true that tankless hot water heaters will always produce hot water, simultaneous demands from different points of use will result in lower water pressure.

Instantaneous Electric Hot Water Heater

On-demand electric water heaters are typically more efficient than gas-fired heaters. One reason why gas-fired heaters use up a lot of energy is because of a continuously burning pilot light. Electric water heaters don’t have a pilot light and require little supervision from the homeowner. Although you are saving energy by choosing electricity as a fuel source for your instant hot water heater, always remember that in terms of flow rate, gas heaters produce higher water pressure. Nevertheless, if your home does not require large volumes of heated water at one time, an on-demand electric water heater will work well. Plus, you will save up to 40% on energy consumption.

Solar Hot Water Heater

In the above discussions, we have focused on the features and benefits of using an on-demand hot water heater. Since the main consideration why you would want to use a tankless water heater is to save energy, it is also important to look at how a solar hot water heater system works and how you can benefit from it. Since a solar water heater depends on the weather, it needs to work in conjunction with traditional water heating systems. If you consider adding a solar water heater to augment the needs of your household, you can reduce your energy consumption and carbon emissions by a whopping 50%.

First of all, solar energy is free and unlimited. If you live in a part of the country with substantial seasonal sunlight, you should think about investing in a solar water heater. What’s best about using solar power for heating water is that the process does not involve converting sunlight into energy, instead, you only need to convert sunlight into heat. The basic set-up of a solar water heater consists of the following components:

  • Solar collector
  • Storage tank

The solar collector is responsible for converting the sun’s radiation into heat, and the storage tank holds water. This typical setup cannot be any more complicated. A solar hot water heater is further characterized as either passive or active. An active water heater makes use of electricity to move water around the system, while a passive solar hot water heater only relies on natural force.

There are also two types of passive solar water heaters which are:

  • Batch. This is the simplest solar water heater set-up. It consists of either one or two water tanks within the solar collector. Heated water inside the tank is forced down into the household pipes using gravity or natural convection.
  • Thermosiphon. The storage tank is separated from the solar heat collector. Cold water travels through tubes connected to the solar collector, and convection pumps move heated water into the storage tank.

On the other hand, there are also two types of active solar water heaters which are:

  • Direct. Electrical pumps move water through solar collectors into the storage tank.
  • Indirect. In a simple solar water heating set-up, water is directly heated using solar heat. In an indirect solar water heater, the solar collector heats a transfer fluid like an anti-freeze, where water flowing through the pipes picks up heat coming from the transfer fluid.
  • Drainback. Similar to an indirect system, a drain-back system uses distilled water as the heat transfer fluid.

A solar water heating system can be expensive, especially if you invest in a more complicated active system. However, there are homeowners who save money by building the simplest set-up, which is the batch-type passive solar water heater.

The monetary savings of using solar water heaters depend on which part of the country you are located if you live in the Pacific Northwest, where sunlight is not as abundant.

Nevertheless, using solar water heaters to augment your home's hot water needs is still worth considering if you want to save money and reduce your home’s carbon emissions. If you have any additional questions about finding the best type of water heating system for your home, contact a specialist from Fischer Heating to guide you.

Contact us for any additional questions you may have, or give us a call today at 206-202-9499.