If you live in an older home with a heating system that is starting to break frequently or is highly inefficient, it is time to start exploring your replacement options. Unfortunately, the structure of old homes can make installing a modern heating system a challenge. Specifically, many old homes have narrow wall spaces that make it impossible to install the large ducts that are needed for modern forced-air systems. The walls might also be built in such a way that it's impossible to access and amend existing ductwork without demolishing your walls or floors.
Luckily, there are options other than standard, forced-air heating. Here's a look at three that tend to work well in older homes with narrow or inaccessible wall spaces.
Hot Water Radiators
Hot water boiler systems consist of a boiler unit in the basement along with a set of radiators through the home that the heated water passes into in order to heat the home. The pipes leading from the boiler to the radiators are much thinner than air ducts, so installing them in narrow wall spaces is no problem. You also won't need to have your walls demolished; your HVAC technician can just feed the pipes in through small holes made in inconspicuous places.
Boiler units that utilize natural gas, propane, oil, and even electricity are available. You can even have a boiler unit retrofitted to coordinate with a wood pellet stove if you want to be able to use a renewable heating fuel. While steam boilers are also available, hot water units (which pass hot water, rather than just hot steam into the radiators) are known to be more efficient and are therefore the preferred choice.
Boiler-style heating is also a good choice if you have allergy sufferers in your home, since allergens won't be blown through the air like they would with any type of forced-air system. These systems also have the advantage of being very quiet. They do, however, require that you have radiators along the wall in each room.
Ductless Heat Pump Systems
This option tends to work best in smaller homes. A ductless heat pump system consists of a condenser unit, similar to the ones used for air conditioning, as well as an air handling unit—or several air handling units. The condenser sits outside. It collects outdoor air and passes it over coils that "collect" the heat from the air. (Yes, even cold air contains some heat). This air passes through a tube that runs along the outside of the home to an air handling unit, which is mounted on the wall. The air handling unit blows the warm air inside. Several air handling units can be coordinated with a single condenser so that you can heat various zones within your home.
This type of system does not require you to install any sort of ducts or pipes within your walls. They run on electricity and are very efficient, so you'll have low energy bills. Their downfall is that they don't work so well in very cold environments—they're best in moderate climates.
Two Standard Forced-Air Systems
This option works well if you have a very large home and don't want to have radiators taking up floor space. You can have one forced-air furnace in the basement that passes air through floor vents to the first-floor rooms, and a second forced-air furnace in the attic that passes air through vents in the ceiling to the second-floor rooms. Since you don't need to get air from one floor to the next, there is no need to run ducts through the walls. The ducts can just be run along the floor of the attic and the ceiling of the basement, connecting the various vents to the furnace. Of course, you will need to have your floors and ceilings modified to incorporate the heating vents. This is usually pretty easy for a remodeling contractor to accomplish.
The upside to this system is that you'll be able to control the temperatures of the upstairs and downstairs independently. Your heating will operate just like the popular forced-air heating in modern homes, except you'll have two systems. The downfall to this system is that it can be a bit expensive, since you'll have to buy two furnaces.
To learn more about heating installation in an older home, talk with an HVAC technician in your area.