Page 491 - 2018 National Home Improvement

2018 National Home Improvement Estimator, All Rights Reserved Page 392

When adding a room, enclosing a porch, expanding attic space or converting a garage, the existing
furnace may not have capacity to serve the addition. Even if the existing furnace has enough capacity, a
long duct run may reduce the volume of heat delivered at the register to below acceptable levels. The
correct way to serve a remote room addition is to install a new trunk line directly to the furnace plenum.
Talk to your heating subcontractor about installing a booster fan in the existing duct run to increase the
flow of warm air.

If tapping into the existing HVAC system doesn’t make sense, and there are no other practical options,
install a floor or wall furnace in the new room addition. Direct-venting thru-the-wall furnaces are usually
an acceptable alternative.

Hot Water Heating
One-pipe gravity steam heating systems are common in older homes. Radiators are fed by a single pipe
on the entry (warm) side. The other side of the radiator has only an exhaust valve on the pipe. Once
steam has cooled and condensed to water, it flows by gravity back to the boiler. This is an extremely
simple system and, if properly installed and maintained, can be a reliable heat source. But again,
one-pipe steam heating systems respond very slowly to requests for temperature change, and they offer
far less control than modern hydronic systems. It may be possible to modernize a one-pipe system by
replacing old radiators with baseboard heaters. Discuss it with your HVAC contractor.

There’s a lot that can go wrong when modifying an old steam or hot water heating system. Results may
not be what the owner expected. Include in your contract some language that limits both the scope of
your work and your liability. For example: Contractor makes no warranty on the condition, size or
capacity of the existing boiler, radiators, or distribution piping.

Radiant heating systems are less common, but tend to be trouble-free. Heated water flows through coils
embedded in either a concrete slab or the plastered ceiling. Expert repair is required when a radiant
heating system’s piping develops leaks or becomes air locked. Breaks in ceiling coils can be repaired
fairly easily. But repairing breaks in a floor is both difficult and expensive.

Electric Space Heaters
Assuming the home has sufficient capacity at the service panel, it’s easy to add electric space heaters
in a home if you need to extend heat to a room addition. However, electric heating is expensive and may
not be practical in colder climates. Also, insulation standards are much higher for a home heated with
electricity, so you must take that into consideration if you plan on this type of heat for your addition.