How to Choose an HVAC System
Whether you're a first-time homeowner or an experienced do-it-yourselfer, choosing a new heating-ventilation-air conditioning (HVAC) system is one of the most complicated tasks you can attempt. Your home's HVAC system is not just a furnace or air conditioner---it is a group of technologies that establish an environment in which you and your family must live for a good portion of each day. Since you'll be living with the machines you install for a long time, it's smart to examine all of your options before making any decisions.
Know the basics. Measure each room and know the volume of all spaces and each floor of the house. Engineers start with volumes to figure "load," or how much power a system will need. They also figure in door and window space, ceiling height, insulation, climate data and other more-abstract factors. Knowing the size of the area you want to design for gives you a place to start. Find out what energy source is most economical in your area and check to see what kind of systems friends and neighbors use. Most local utility companies offer "energy audits" to help customers identify ways to save energy.
Find out what's practical. In some areas, heart pumps don't save much energy or money because the winters are too cold or summers are too hot for them to function efficiently. An air conditioner may have to work less if it's installed on a flat roof or it may be better to install it on the shady side of the house, again, depending on climate. Air conditioning can be installed with a radiator (steam or hydronic) or radiant heating system, but it's less expensive if the duct work is already there for a forced air system.
Hire a contractor that you trust then depend on his expertise. Check references and credentials---states certify contractors. Consult with several contractors to determine what the specifics you want included in your HVAC will be then ask for bids on what you decide will be the essentials of your project. Throw out the low (probably underestimated labor) and high (probably used expensive parts) bids and choose the contractor in the middle group that you trust and who listens and answers your questions most satisfactorily. Then work out details and let your contractor do the job without second guessing. If you see something that you don't understand, ask a question. Your contractor's final task is to explain how everything works in excruciating detail. Be sure to ask what can go wrong and what to do when it does.
Check into filters, humidifiers and dehumidifiers if they are not built into the heating-cooling plant. Older homes may have problems with mold and materials like asbestos insulation that must be addressed before installing a new HVAC system. In today's well-insulated and sealed buildings, "off-gassing" of building and furnishing synthetics and materials may also need removal so they don't continue to be recirculated through the building.
Investigate alternatives. Find out if there are rebates or energy credits offered for certain types of equipment and if alternative fuels like solar or wind-powered equipment is an option in your area. Be sure to base decisions on "pay-out," compare the cost of the unit to how much energy it will use and its probable life expectancy to see which equipment is the most economical.
Things You Will Need
- Access to HVAC information
- Reliable contractor
- Recent energy audit if replacing an existing system (optional, but recommended)
- In addition to checking furnace ratings and EER's before the job starts, keep track of warranties and service contracts, and maintain equipment according to schedules.
- Use a contractor to install your HVAC equipment who also services it--or has relationships with people who do.
- Ask as many "stupid questions" as you need to. If your contractor isn't happy to discuss HVAC systems, you want to find one who is fascinated by their components and composition.
- Along with providing all applicable building permits, require a performance bond from your contractor--successful professionals are used to working for customers who expect them.
- One of the first mistakes people make is to over-build a system (buy equipment with too much power) and the second is to "economize" and build a system that's not up to the task.
- An HVAC system is one of the most expensive purchases you'll ever make--retrofits can cost as little as 5000 dollars but new systems can run into the tens of thousands. Take your time making decisions and demand that your contractor respects and sticks to your budget.