06 Mar What Is the Best HVAC System for Your Home? A Straightforward Guide
In the cool, damp climate of Seattle efficient climate control and airflow are important for your comfort and health. Mold spores and mildew can cause unpleasant and uncomfortable symptoms in many people. Control of temperature and moisture are important.
HVAC systems are a not insignificant part of your total energy consumption (about half for most homes.) Energy efficiency and cost are major considerations in Washington.
If you are ready to replace your HVAC system, there are so many factors to take into account. What kind of unit? What size? What fuel?
What is the best HVAC system for your home?
Read on for our straightforward guide.
Clearing Up the Alphabet Soup
One of the first things to clear up as you look for an HVAC system (Heating, Ventilation and Air Conditioning) is the industry passion for acronyms. Here’s a short list of some you may see often.
These industry-specific terms are frequently used in sales materials and documentation for HVAC systems.
- AFUE: Stands for Average Fuel Utilization Efficiency. This measures efficiency for gas and oil-fired furnaces. A high-quality furnace can have a rating of up to 98.6%. This means that the furnace converts 98.6% of fuel to heat air and the remaining 1.4% is sent up the flue as waste.
- BTU: Stands for British Thermal Unit. This is a standard measurement of heating and air conditioning capacity.
- CFC/HCFC: Chlorofluorocarbons/Hydrochlorofluorocarbons. These substances are found in refrigerant and foam insulation. Most were banned in 2010. Older appliances may still have them.
- COP: Stands for Coefficient of Performance. This ratio compares the amount of heat delivered to the amount of energy used to produce that heat.
- HSPF: Heating Seasonal Performance Factor. A numerical rating of heat pump heating equipment efficiency. Look for a number 8.2 or higher.
- R-22: A type of CFC-based refrigerant no longer manufactured after 2010. It will be phased out completely by 2020.
- R-410A: The replacement for R-22, although it still has affects the ozone layer.
- SEER: Seasonal Energy Efficiency Ratio. This is a numerical rating of the cooling efficiency of central air conditioning and forced-air heat pump systems. High SEER numbers mean more efficiency. Look for 14 and above.
You will find many abbreviations thrown about. Don’t be afraid to ask for clarification.
What Is the Best HVAC System for Your Home?
Start with a basic home audit. HVAC systems are not a one-size-fits-all proposition. You need to “right-size” your system from the very beginning. There are some specific calculations to determine the ideal system size.
Someone from your local utility or the contractor determines the square footage of the home and air volume. The building’s construction, the number of rooms, windows, and doors, the quality or R-value of insulation are all considered. Solar gain, local climate, and the building’s thermal efficiency are all part of the load calculation.
You might hear the words “Manual J” during this calculation. This is one of the tools published by the Air Conditioning Contractors of America to help HVAC contractors design systems. Beware of “estimates” based on only square footage.
Load determination by a single variable leads to an over-sized heating and cooling system. This gives an increased initial cost, increased monthly utility bills and increased maintenance. Also, the frequent equipment cycling shortens the expected equipment life.
Choose Your Heat Source
Oh no, not the alphabet soup again. Variable-speed, single-stage, multi-stage, power-vented, true modulating, etc. You can easily get lost in the weeds.
What is the best HVAC system for your home? The answer is: “It depends.”
For the most part, you have a few basic choices.
Natural gas, electricity, propane, or oil heat a metal plate that heats a mixture of fresh and recirculated air. The hot air is circulated through the house in air ducts. The same ductwork is used for heating and cooling.
For people with allergies, the moving air can be very irritating. The air is very dry and contains dust and allergens. Filters must be meticulously maintained to maximize efficiency.
Furnaces come in single-stage (burner is ON or OFF), multi-stage (burner is HIGH, LOW or OFF) or true modulating (burner heat is variable). The blower can be single speed (ON or OFF) or variable speed. Heat is measured in BTU.
Boilers work in much the same way as furnaces, but they heat water. The hot water or steam is then circulated using radiators or radiant floor systems. Modern boilers also provide hot water, eliminating the need for a separate hot water heater.
Radiant floor systems provide an even, gentle heat. Warm floors are very comfortable and hold heat longer than warmed air. Because they do not rely on circulating air, they do not spread dust around.
They require very little maintenance and are very quiet. However, you will need to maintain a separate system of ductwork for air conditioning during the summer.
Heat pumps are extremely efficient systems for mild winter areas. A heat pump pulls heat from air, water, or the ground and transfers it to air inside your home for heating. It uses the reverse of the process to cool your home.
Heat pumps work best in moderate climates. They come in ducted and ductless versions. Some heat pumps also have a heat recovery system that transfers extra heat to heating water. Heat pumps work best with a backup burner for the very coldest days of operation.
There is a ductless mini-split version of the whole house heat pump available. They are widely used in Europe. They require one unit in each zone. They are ductless and lose no heat to travel.
Choosing the Air Conditioner
All air conditioners work the same way. The refrigerant is sealed in a series of metal coils and warm air circulates around the coils. The heat is absorbed by the coils and the cooled air is circulated back into the house.
The heated refrigerant is circulated to the compressor outside and the heat is pumped off. The cooled refrigerant is pressurized back to a liquid and circulates back to the heat exchange coils. Efficiency is measured by SEER; a bigger number is more efficient.
A right-sized cooling system is important. Over-sizing the system means that air cools faster, but may not adequately remove moisture from the air. This can cause mold and mildew problems. Air conditioners are sized in tons, which is the cooling power of one ton of ice melting over one day.
Heat pumps are efficiency rated the same way as air conditioners. If you are in a mild climate with short winters, a ductless heat pump is one of your best choices.
Check Your Ductwork
Forced-air systems rely on well- designed and maintained ducts for top efficiency. Poorly designed or leaky ductwork negatively affects efficiency. Duct efficiency is part of the unit size determination. Efficient ductwork lets you install a smaller system.
Inspect your ductwork for leaks at points where two pieces of duct meet. Check the area where the ducts join the air handler and the registers for tight seals. Unsealed or leaking ducts can lose 30% or more of the air they transport. Check for duct insulation too.
Dust buildup in ducts or filters reduces system efficiency. Regular filter changes and occasional ductwork cleaning keep indoor air quality high. It also keeps your heating and cooling system from working harder than it should.
Do the Math
A new heating and cooling system is a major investment. You should expect a 15-20 year lifetime for the equipment. More efficient equipment can be more expensive in the beginning, however, calculate your energy costs over the expected lifespan. You may find that the highest efficiency model makes good sense.
Also, look at maintenance costs. Ductless systems like radiators and boilers have very little ongoing maintenance. Their initial cost is high, however, and system failure can cost many times more than just replacement of the system if leaking water damages your structure.
Heat pump systems have fairly simple maintenance needs, especially if they are ductless and their energy use is comparatively low. They are especially cost-efficient in areas with moderate climates and high energy costs. They can have high initial costs, though.
Ask about different options. Combining certain units or opting for ductless mini-splits could be more economical than a large initial purchase.
Ask Our Experts
“What is the best HVAC system for your home?” Is a question we hear often. Let our experts help you calculate the right size system for your home and the way you live. We have more than 30 years of experience in the Greater Seattle area.
We install, service and sell HVAC systems with the highest levels of professionalism and quality. We handle furnaces, boilers, ductless heat pump systems and more. Contact us today.