Is It Your Windows or HVAC Unit?
With the rise of energy costs, homeowners everywhere are facing an expensive decision: do they upgrade to a new HVAC system or new windows and doors to help with the bills? Both are significant investments that directly impact your home’s comfort and efficiency, but rarely does a budget allow for updating all at once.
If you are trying to determine which update will have the most immediate impact, it helps to look at how these systems work together, and where they might be working against each other.
Identifying the Problem
First, you will need to identify the reason for your high utility bills. HVAC and windows and doors all contribute to climate control, but they play very different roles. Your HVAC system generates treated air, while your windows and doors seal that air inside.
If you notice that your HVAC unit cycles on and off or find dust near your vents, the mechanical system may be struggling. However, if you feel a draft of air while standing near a closed window, or if you see condensation trapped between double-paned glass, the door or window seal could be the culprit(s).
Modern HVAC Impacts on Older Windows
If your old windows and doors are drafty, a high-efficiency HVAC system might provide a benefit, but there is a caveat. Modern systems, particularly heat pumps and variable-speed central air units, are far more adept at maintaining consistent temperatures than older models. Even if some air is escaping through older seals, a new unit will reach your desired temperature more quickly and use less electricity to stay there.
If your current home uses baseboard heating or older mini-split units, upgrading to a high-efficiency central system or a modern multi-zone heat pump can lower your bills regardless of your windows. Modern systems are designed to modulate their output so they don't have to work at 100% capacity all the time. This saves money even in a less-than-airtight house.
When Windows and Doors Take Priority
If you have rooms that are significantly colder or warmer than the rest of the house, it is often a sign your doors and windows are contributing to air leakage and it might be worth looking at upgrading to double or triple-pane windows with Low-E coatings. These windows stop drafts and reflect heat. In the summer, this keeps the sun’s rays from baking the inside of your house, and in the winter, it prevents heat from escaping. If you choose to upgrade your windows first, you can often keep your older HVAC system longer. Your old furnace or AC won't have to work as hard, potentially extending its lifespan and lowering your monthly energy bill.
How Doors and Windows Interact with HVAC Systems
The way your HVAC interacts with your home’s seal depends heavily on the type of technology you use. Central air and furnaces rely on high-volume airflow. If your windows are leaky, the conditioned air is pushed out of the house. Ductless mini-splits are excellent for older homes with window issues because they allow for heating or cooling zones. This means you can crank the heat in a drafty room without wasting energy overheating other rooms that are well sealed. Finally, heat pumps are very efficient but work best when the home can maintain a steady temperature. If your windows are original to an older home, a heat pump has to work much harder to keep up with how much heated air is leaking.
Windows or HVAC? Here’s How to Choose
If you are forced to choose one, consider the following checklist:
- Check the age. Most HVAC systems have a lifespan of 15 to 20 years. Windows can often last 25 to 30. If your furnace is older than 20 years old, consider replacing the HVAC first.
- Evaluate comfort. Is the whole house expensive to heat (HVAC issue), or are there certain areas or rooms that get colder than others (window or door problem)?
- Analyze the Tech: If you are currently using smart thermostat solutions and still see no improvement in your bills despite windows and doors being a reasonable age, the mechanical system is likely the weak link.
Making a Strategic Investment
Your goal is to create a home that is both comfortable and sustainable. Most people aren’t able to upgrade everything all at once, so making an informed choice based on the current state of your equipment will save you the most money in the long run.
If you are still unsure which upgrade will provide the best return on investment for your specific floor plan, the team at A Plus is here to help. We can evaluate your current residential HVAC setup and help you determine if a system replacement or a structural upgrade is the right move for your budget. Schedule an appointment online today, and get a professional opinion on your home's energy efficiency.
