Zone control is certainly not the newest improvement to a heating system’s efficiency, but it is something that is often cumbersome to adopt in older homes. Zone control refers to a home’s ability to separate out different rooms or levels on a heating system’s demand, most commonly by the use of circulator pumps on forced hot water heating systems. There is some ability to zone out HVAC systems, but these often also maintain one common zone (unless you have multiple systems). Steam systems present the biggest challenge to zone control, as they are inherently all connected through a system of radiators that run off of a single thermostat in a home. Without the ability to control the temperature of certain areas independently, you are left with a heating system that often results in an unbalanced and inconsistent heating supply.
Replacing single-zone systems with a multi-zone system
One of the more popular home upgrades in past years has been to remove single-zone heating systems like central furnaces or steam boilers and replace them with a multi-zone capable forced hot water boiler. Forced hot water boilers, unlike steam boilers, rely on circulation pumps to move the hot water through each part of the home, depending on your plumbing setup. Generally, a forced hot water system will be designed to have at least 1 zone per floor, if not more depending on the layout and budget constraints. These individual circulator pumps can be controlled by their own thermostat, effectively controlling what room you are heating and to what temperature. The best practice here is to heat each room as needed and set back thermostats to areas where heat isn’t required. Because of the heat fossil fuel burning generates, it’s more cost-effective to set heat down much lower than you would for a comparable heat pump setup. The forced hot water baseboards are good at bringing a room back up to temperature relatively quickly. Turning the heat down in the bedrooms during the day and turning the heat down in the shared space during times when the residents are asleep will yield the best energy savings.
Programmable thermostats come in handy for these types of heating setups. You can program each thermostat to start heating a room half an hour to an hour before it’s expected to be used to compensate for the time it takes to reheat. Homeowners will find that setting back thermostats and programming them to raise back to temperature when leaving the home maintains comfort levels while also minimizing fuel burned.
Any person with a forced hot water zoned home gets the same advice from me, don’t pay to heat a home when no one is around to enjoy the comfort. Keep temperatures set low and program thermostats to raise temperatures in anticipation of occupants returning to the areas. It is a common myth that it takes more energy to heat a home up from a low temperature than it does to maintain a temperature consistently for the same amount of time.
Heat pumps to offset single-zone
While it’s not always feasible to completely replace a steam heating system with a comparable forced hot water system with zones, new technology in heat pumps does allow the potential for gaining zone control beyond what any steam system could provide. You may be familiar with ductless mini split heat pumps and their most common form of installation is the wall-mounted units that will exist in each room in a home. Installing these heat pumps either fully replacing steam heat or working in tandem with the steam heat gives the user much more control on which rooms are heated and cooled to what degree.
Sometimes, completely removing a single-zone system like steam heat makes sense. Either the boiler is past its expected life, or maybe the homeowner just wants to free up space on the floor/in the basement where the equipment sits. Both of these are valid reasons to justify the full removal of a steam system. Other instances where a customer may have a perfectly fine steam system may justify the addition of ductless heat pumps to offset the need for steam heat. Because each ductless heat pump works independent of the other heat pumps, you can easily close off less frequented spaces like a guest bedroom or unused 3rd floor, lessening the overall heat load that your home demands. If/when the time comes to bring those rooms to temperature, bringing heat pumps back online will do this slowly but surely.
Only heating the areas of a home when needed can help lessen your overall fuel consumption saving you money in both the short and long term. Whenever temperatures drop to below the level that heat pumps can efficiently perform, having that single zone steam heat as a backup will come in handy work as a secondary system.