Heat is not a luxury for homeowners in Connecticut. Air conditioning on the other hand is not really a necessity. While it does at times get very hot in the summer, intense heat is not usually around for long.Heating systems here typically can be run from as early as October to as late as April. Therefore a properly working heating system is a must.
When performing a home inspection testing the heating system can be said to be a major part of the process. This includes the distribution system. Some systems are forced warm air, blowing heat from supply registers in each room. Others are hydronic, circulating hot water through pipes to radiators.
Personally I like hydronic heat. The radiators give a warmer feeling to the room. Forced air doesn't seem to have the same feeling, probably due to the lack of a heat sink. Air doesn't hold heat long.
Both types of systems have gone through changes over the years. Older houses with forced air systems are usually installed "backwards". The supply registers being at the back of the room, while the return air ducts are opposite, along the exterior wall.
Hydronic heat is distributed by pipes to the radiators or is the pipes in the case of a radiant floor. There are basically three types of hydronic systems, gravity feed, forced hot water and steam.
Gravity feed is antiquated and extremely inefficient. I almost never find this type of system. Steam is still quite common. Gravity feed and steam systems are predecessors to the forced water systems of today.
The big difference between the first two systems and the latter, is of course the pump. Not as well know and very important is the piping configuration. Steam and gravity fed systems have a different distribution pipe configuration than a force water system. The differences are necessary in order for each system to operate properly and more importantly, efficiently.
Checking the radiators in an older home not long ago, I found two "dead" radiators and a third one appeared to need life support. Further the kitchen did not have a radiator at all, instead there was what looked to be an electric heater that when tested produced zero heat. Slightly more than half the radiators were functioning, with the dead zone following a distinct pattern. Interestingly in the living room of this ranch style home was a wood stove, begging the question, was it an accessory or a necessity.
In the basement I found what I have come to know is often the piping configuration in a house of this age with this particular distribution issue. The pipes are configured in what I call a steam system pattern (Mono flow). This is where there is a single main pipe loop to and from the boiler. Each radiator is looped off this main pipe. This works for steam, not well for forced water. What effectively occurs is the water attempts to push into both ends of the loop. This problem is solved usually by installing different diameter pipes at each end of the radiator or a kind of valve on the feed side. In this instances I saw none of these solutions.
Because of the poor flow characteristics, the pipes at or in the radiators are likely clogged with sediments. This combination has render the heat distribution at the lower portion of loop just about completely dead.
A poorly operating heating system is an undesirable element.