Natural gas combi boilers make economic sense for the home

With the passing of summer, the attention of many homeowners shifts onto preparation for the winter season. Boats and docks need winterizing, gutters need clearing, and home heating and hot water systems need to be checked to ensure they are in good working order. Not only must they be able to function, but they must also be able to operate efficiently to prevent utility bills from rising sharply.

Natural gas is an environmentally friendly fuel that is far more energy-efficient than electric systems. That’s why many homeowners are switching from electric to natural gas systems. But even those who already use natural gas for home heating and hot water are considering an option that could increase the savings even more – the installation of a combination boiler/hot water system.

“It’s often best to combine home heating and hot water as it’s much more efficient,” said Richard Trethewey, a master plumber from Boston, Massachusetts, who installs hot water and heating systems.

Combi boiler basics

Combination or combi boiler systems help homeowners save money, space, or both. On the financial side, the savings quickly mount up. According to a Green Affordable Housing Coalition report, combination water and space heating systems can reduce utility costs by 15% or more than standard installation of separate furnaces and water heater systems.

How about space? Instead of a large water boiler or furnace taking up lots of space in the basement or garage, one compact appliance provides all the heat and hot water required by the entire household – and does it efficiently, saving on both operating and installation costs. Trethewey noted that far less piping, venting, and wiring are needed within a combi project than traditional boiler and home heating arrangements.

While conventional systems store domestic hot water in a large tank, combis heat water in the same way as a tankless water heater. This is accomplished via a second heating circuit, which supplies hot water whenever it is needed. This feature alone eliminates the need for a hot water cylinder, a loft tank and related pipework. As all parts of a combi system are contained within a single unit, they are much easier to install.

Home replacement

Trethewey installed a combi system in the basement of one home in Massachusetts. One small system replaced a large, aging, hot water heating system. Water was heated in the boiler and transmitted to convectors in each room to provide heating.

Over on the other side of the basement stood a traditional tank to provide hot water – always using energy whether hot water was needed or not.

“A small gas-fired combination boiler provides both heat and hot water for the house,” said Trethewey. “One small unit replaced the large water tank and home heating system.”

Unlike a traditional boiler, the burner for hot water is only running when the faucet is turned on at a sink, bath, or shower. As there is no tank to heat up, energy savings can be substantial.

Home-heating and cooling versatility and efficiency

What sometimes isn’t realized is just how versatile combi boilers can be. As well as pairing home heating with hot water production, the presence of a hydronic air handler means that the system can supply cool air in the summer. Ducting would have to either be present or added.

Such a system makes maximum use of the available energy from a small amount of natural gas. This is yet another way natural gas offers a way to lower the carbon footprint of the home compared to the use of electrical systems for hot water, heating, and air conditioning.

When it comes to home heating and cooling, combi boilers also maximize efficiency to keep bills low. How? Old heating systems tend to have rigid temperature set points that cause too much fuel to be consumed. This results in systems that overheat the home, especially during spring and fall. On the other hand, some modern combi boilers are designed to have flexible set points that adjust temperature settings when the air is not as cold outside. In other words, they only provide the exact amount of room heating needed and no more.

In short, with winter approaching, natural gas combi boilers make sense on several fronts. They are good for the environment and have proven to be energy efficient, enabling the homeowner to have more cash to save for the holiday season.

This article originally appeared in the Fall/Winter 2021 issue of Natural Living, and was authored by Drew Robb. To read more articles about utilizing natural gas in your home in Natural Living, click here.