Basic Phrases In Heating
This section is meant to help people with basic phrasing regarding heating and cooling. With hundreds of Massachusetts homeowners calling our company every year, it is normal that not everyone understands how to describe what they have for a heating system, or even more so what they ideally want or need.
You generally have either one of two classifications in your home: HVAC or Hydronic Heating. HVAC stands for Heating, Ventilation, Air Conditioning, but it widely accepted as referring to a ducted system, also known as forced warm air, forced hot air, central AC, central air, or a combination of these terms. The other popular method of heating is Hydronic Heat. Hydronic heat is very popular in the New England region of the country (and certainly in other pockets of the country as well). It refers to either hot water heat or steam heating. Many regions of the country are strictly HVAC, such as urban sprawl communities and high volume housing developments. However, when it comes to residential neighborhoods in older small cities in New England, you would be hard pressed to find warm air systems.
When you describe what kind of system you have to someone, you generally describe two subjects in the same breath: the fuel (or energy such as electric, solar, or geo-thermal), and then the kind of system (as described here). So, you might say, I have a natural gas hot water baseboard system, or I have an oil fired forced hot air system with AC. Most folks in the industry say the energy used first, then the type of system.
Hydronic simply refers to water
It typically refers to hot water or steam
Steam and Hot Water used cast iron radiators up to the 1940s and early 1950s.
Steam heat was popular up to World War Two. You know you have steam when you hear your radiators hissing. Some steam systems don’t hiss though; they have a second pipe (known as two pipe steam) that vents the air out of the radiator. Most average houses have one pipe steam, which is when you hear the hissing.
Steam systems can be problematic for reasons such as: the returns may get clogged up underground in the basement, the vents may become inoperable, the low water cutoff may cause the boiler to fail, unenlightened heating technicians will mess with the pressure setting causing problems, and many steam systems still are insulated with asbestos insulation.
Steam is the least efficient way to heat because it takes so much energy to create steam
After WWII, hot water heating became the standard; steam became too expensive to install and it was less efficient than hot water heating
The modern baseboard heating is extremely popular in New England states, and in other pockets of the country.
Hot water heating can be very versatile. You can have a life-time warranty water heater, you can have warm floors in the bathrooms (or the whole house for that matter), you can have a small ceiling-hung or wall mounted heater in a garage or work shop, you can even have towel warmers that are decorative and functional.
Hot water systems are very zoning friendly. Its much easier to split a hot water heating system into multiple zones than a warm air/AC system.
Most hot water systems use pipes 1 in diameter or smaller, taking up much less space in the basement compared to a typical duct sized at 10 by 24. That’s 240 times the area for a similar amount of energy delivery. Its because the heating value of water is several hundred times greater than air.
In Europe, where fuel is extremely expensive, hot water heater systems rule. There are laws (at least in most countries) where there are strict design requirements that must be met. A handful of contractors in the USA are familiar with these installation techniques and have an excellent understanding of the mechanics to obtain high efficiency. Its unfortunate than most installers do not understand these concepts.
Benefits: For steam systems there are none, other than keeping with the original ambiance of a 100 year old house or avoiding 5-digit heating renovation costs. For Hot Water systems, there are many: Versatility and zoning as mentioned above, fuel efficiency when the right contractor is hired, generally higher comfort because of the lesser air movement.
Draw backs: Air Conditioning is not an option, you’ll need a completely separate system (many homes do have both).
Warm air and central AC uses duct work. These ducts are usually galvanized metal, but sometimes you might have duct board, which is a rigid fiberglass board cut to form duct work. Duct board isn’t all that popular because it can potentially collapse in humid climates. Also, the run outs may be either round or rectangular (maybe even square) sheet metal, or another popular way to duct the run outs is with flex duct. As the name refers, the duct is flexible. However, flex duct has its disadvantages.
If your heating system has grilles, registers or diffusers in the floors, walls, or ceilings of your home, you have warm air.
If you have warm air for heating, you usually have what’s called a furnace or an air handler. Furnace refers to an appliance that has a burner, either gas or oil. An air handler is similar to a furnace, but it doesn’t have a burner. An air handler may get its heating energy from a hot water boiler, or sometimes electricity from a heat pump or electric resistance heat (like a big toaster), or from a geo-thermal system. An air handler does just that, it handles air.
Because the building industry has yet to settle on defined industry standards, consumers unfortunately cant identify between a quality duct system and a poor duct system. Lets be real for a moment: the low-budget duct installer wont come out and tell you he’s giving you sub-par work. If you do your homework, you will be able to know what you’re getting for your dollar.
Benefits: You can have heating and cooling in the same system. You can have conditioned air meaning a high quality filter system for families that need higher quality air to breathe. You can deal with the sometimes brutal humidity in the summer with even a small AC system installed. You can add a humidifier to the system to help out with the desert-like dryness in the winter.
Draw Backs: Its harder to install the ideal system. Its also much more expensive. Unlike water (Hydronic heating), air needs to be forced down big ducts. If the ducts are not designed right, the static pressure can become too high and the blower motor wont be able to move the originally intended volume of air. Besides restrictive duct work, another huge concern is leaky duct systems. Unlike water systems (you would know really quickly if your hot water heating system was leaking), ducted systems are notoriously leaky. High quality duct systems leak very little; poor quality duct systems leak like sieves. Leaky ducts mean high energy costs.