What can I do to save on energy costs?
There are many ways to save on energy costs. The easiest things that a homeowner can do are:
- Adjust your thermostat up or down 5 degrees depending on the time of year
- Program the thermostat to adjust the temperature depending on the hours of the day
- Install ceiling fans
- Ensure vents are not blocked in regularly-used rooms
- Block vents in less-used rooms
- Have annual tune ups performed
- Upgrade to a high-efficiency system
What does a “tune up” on my HVAC system consist of?
Tuning up your HVAC system is a diagnostic checkup in which a certified technician checks and adjusts the various components of the system to ensure that it is performing optimally. It includes important things such as: check unit for optimal performance (and adjust if necessary), inspection of carbon monoxide emissions, inspection of ignition system, inspection of gas lines and valves for leaks, inspection of ductwork for leaks, calibration of thermostat, and much more.
A tune up is important 2 reasons: It ensures that your home is heated/cooled properly. It also ensures that your HVAC unit will have the longest life possible before it is necessary to replace the entire system.
Is it time to replace my HVAC system?
The average life of an HVAC system is 10-20 years. The specific time is effected by the model of the unit itself, the weather where you live, and how well it is maintained over the years.
There are a few signs that indicate that your HVAC unit is ready to be replaced. If your HVAC unit is 7 years old or older, is constantly running, fails to warm or cool your home properly, or your utility bills are unusually high, there is a good chance that it is time to replace your system.
Replacing vs Repairing
When it’s time to consider repairing or replacing your existing HVAC system, consider the following: upfront costs, and monthly cost of ownership. Many home owners make the mistake of simply comparing the upfront cost of a repair with the upfront cost of replacing the system. However, the monthly cost of ownership should also be considered.
The HVAC system in your home will become more and more inefficient as time passes. Older units tend to work harder to make your home comfortable. Additionally, newer HVAC units offer dramatic improvements over units produced just 10 years ago. When all things are considered, a newer HVAC system may save you a large amount of money every single month on your utility bills.
What can I do to take care of my HVAC system?
The first thing you can do is to make sure your units are tuned up on a yearly basis. Furnace units should be tuned up in the fall, and air conditioning units should be tuned up in the spring. It only takes one time of having your furnace turn off in the middle of the night to learn that preventative maintenance is critical.
Also, it’s also very important to replace your air filter on a regular basis. You should visually inspect your air filter every single month. If it is dirty enough to prevent the proper flow of air through the filter, it’s time to change it.
What size system does my house need?
Proper equipment selection is a process we call a Load Calculation.
Load calculations determine the “load” or amount of heat that a structure needs to be removed or added to maintain a steady temperature. Sometimes this is referred to as “heat loss /heat gain”. Measured in Btus/Hour (load). The load is affected by things like Windows, attic insulation, local climate, humidity etc. – (ACCA Manual J)
Once the Load is determined we select the equipment based on capacity. The capacity of the equipment is also measured in Btus/Hour (capacity), or tons. (12,000 Btus/hour = 1 ton nominal). the goal is to match the capacity to the load as closely as possible. To match the capacity to the load we need to adjust the nominal capacity of the equipment to the actual capacity expected in the real world. The capacity is affected by things like altitude, local climate, air flow, humidity etc. Not making these corrections to the capacity can lead to undersized AC units in some climates. (ACCA Manual S)
The properly sized AC or heating system for a home is the one that matches the capacity to the load after all adjustments have been accounted.
I was told that 400 sq ft per ton was a good way to size an AC unit. Is that correct?
No. Unfortunately, there are no rules of thumb that can be used to size and AC unit.
Didn’t the builder of my home size the system properly when they built the home?
Not usually. Home builders historically have used rules of thumb to size AC and Heating systems. Builders often want bigger systems as a matter of pride and ignore the proper methods in favor of oversizing. This is so prevalent in the building industry that it is rare to find a properly sized AC or heating system on an existing home.
“Wont a smaller unit work harder?”
This question can be meant two different ways. The most common is a question about reliability. Motors that are running as intended are more reliable, not less reliable. Motors do not “work harder” they just do what they are designed to do. The engineers that design the equipment are the same engineers that wrote the book we use to size equipment. We should give them the benefit of the doubt. Oversizing the equipment leads to more on-off operation which significantly reduces reliability.
The other way the question is meant is about cost to operate. The belief is that a smaller system will run longer and thus the utility bills will be higher. Smaller equipment does run longer, but it uses less electricity while running, and fewer on – off cycles. On -off cycles use more electricity and should be avoided.
The other contractor said I need a bigger unit, and he has been doing it for 20 years and does not need a load calculation to know.
Perhaps the most frustrating objection to doing it right, is the fact that so many contractors do it wrong. Good contractors are a minority in the HVAC trade. It is this truth that makes this FAQ necessary in the first place. The reasons contractors do it wrong are numerous; cost, training, time are among them for sure. When a contractor tells you that they do not need to perform proper equipment sizing they fall into one of these categories: They are being untruthful, they have never been taught, or they are lazy. In all cases they should not be doing work on your home.
If you have any questions about the efficiency of your HVAC system, call J & M Air Conditioning & Heating to schedule a free consultation with our trained professionals.(951) 654-3464