HVAC Buyer's Guide
Whether you need to replace a furnace in an older home, or are in the process of designing the heating and cooling system for a new home, the sheer number of home heating and air conditioning choice can be mind boggling.
If you've spent any time reading the specifications of furnaces, air conditioners, heat pumps, humidifiers and other equipment, you may be more confused than when you started to shop.
comfort and value.
You want to be warm and comfortable in the winter. You want to be cool and comfortable in the summer. You want year-round comfort no matter what the weather brings. You want to save energy and save money. You want trouble-free equipment that lasts and continues to save money each year.
Knowing a little heating and cooling lingo can help... In general, all Heating, Ventilation and Air Conditioning equipment and services are referred to as "HVAC".
(Note: use our online HVAC Definitions for more heating and cooling definitions).
Before getting into the specifics of which type of HVAC system is right for your home, or what the different benefits and features of one type of system or another offer, it helps to understand the term "value" as it applies to HVAC.
Like many items you don't purchase very often, when shopping for an HVAC system, the difference between price and value may be hard to understand. While price is the amount you pay for an HVAC system "today", value can only be looked at over the long term.
If one system costs several hundred dollars less to buy, but will use more energy to operate, or worse, will only last a few years before it needs major service, that system is not a good value.
You may be asking yourself; "How do I know what the right HVAC system is for my home?"
An HVAC system's basic function is to provide heat and to provide cooling. The system can also control humidity and filter the air in your home. Systems which perform all four functions provide you with greatest year-round comfort.
Understanding your home's HVAC energy needs, is a good place to start. No matter which type of system you choose, the system will need to be able to heat and cool the living space in your home.
The system needs be properly sized. A system that is too small will run too often, may not be able to get the house to temperature, and wear out before it's time. In the case of air conditioning, a system that is too big will "short cycle", meaning it doesn't run long enough to remove the humidity from the home, and other mechanical problems with the unit can occur.
You wouldn't buy a pair of shoes that were too large or too small, you'd be uncomfortable and it would cause other problems -- the same applies to HVAC purchases.
Sizing an HVAC system requires that you take into consideration the number of cubic feet of air the system will heat or cool. Since most homes have standard (8') height walls, sizing can usually be based on square foot of floor space. While many older homes may only be 1500 to 1600 square feet, many newer homes are in the 2,300 to 2,500 sq. ft. range.
There is no simple formula that works for every home. Every building is different. Some of the other factors that need to considered to properly size and engineer an HVAC system are:
- How well insulated is the structure? - a well insulated home will require less work from the heating and cooling system.
- Are there any walls that contain large areas of windows? - traditionally doors and windows are a major source of heat loss, air infiltration, and in warmer weather can create the need for additional cooling due to heat produced by sunlight.
- Are there high ceilings? - in older homes built using traditional construction methods, most rooms had walls that were 8 feet high. Many newer homes are built with large open areas, "great rooms", multi-story entry way or foyers which present additional heating and cooling challenges.
- Is all living space on a single level or spread between several? - if all living space is on a single floor, it generally means that there is more exterior wall space than in multi-level homes. Insulation in exterior walls must be considered. In multi-level homes, warm or cool air can be moved from one level to the next conserving some of the energy.
- Are there rooms that aren't frequently used, but need heat and cooling? - In homes with finished basements, attached offices, guest rooms and other living space that is not always in-use, it may be more efficient to install a multi-zone system where a thermostat in each zone can control temperature independently.
- If updating; Is duct work already in place? - if you are replacing an outdated HVAC system such as an oil fired furnace and window air-conditioners, you will need to decide between having duct work installed or using a duct-less HVAC system. If replacing an older central HVAC system, the duct work must be checked to make sure it's in good shape and properly configured to handle the air-flow of the newer system.
- Does the home's interior lighting causes excessive heat? - rooms with a lot of bright electric lighting may require additional cooling consideration.
- What level of noise is acceptable? - where the HVAC system is installed, either inside or outside the home, and how close the mechanical components are to living space, (and neighbors homes), can be a consideration.
Since some HVAC units run on electricity, others on propane or natural gas, and others on home heating oil, its easier to think of any of these fuels simply as "energy" and compare how much energy they produce on a dollar for dollar basis.
Budget is also considered and budgeting factors may include how long you plan to own the home or business, if its rental property or owner occupied,
Once all factors are considered, an experienced HVAC system designer can determine which type of system will best meet your needs.