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When Is High Efficiency Too High? Your HVAC Purchase Guide
High efficiency might just be the marketing buzzword of the 21st century. This term is used to highlight all kinds of good things - lower energy bills, fewer emissions, less consumption of fossil fuels.
But a high efficiency furnace and air conditioner are not always the right choice for every person, or for every space.
Just like high performance sports cars conk out when forced to idle in stop-and-go rush hour traffic, a high efficiency HVAC system is only going to work well when installed under optimal conditions.
In this timely blog post, learn when high efficiency HVAC systems work well and when another option may be a better choice. Your Shipton’s technicians offer HVAC in Burlington, Oakville, Hamilton and surrounding regions!
What Does HVAC Efficiency Mean?
The word "efficiency" refers to how well the appliance converts fuel input into energy output. Let's take a look at what this means for both an air conditioner and furnace.
Air Conditioner Efficiency Ratings
For an air conditioner, the unit of measurement you want to look for is Energy Star's SEER rating. SEER stands for Seasonal Energy Efficiency Ratio.
You can also look for EnerGuide's EER rating. EER stands for Energy Efficiency Ratio. SEER ratings can go all the way up to 21.
Here in Canada, all new AC units are required to carry a SEER rating of 13 or greater. Units rated 14.5 or higher are eligible for an Energy Star label.
Units with a 17 to 21 SEER rating are considered HEPA-ready (in that they can operate efficiently even with a high-density HEPA filter installed).
How can you use the SEER rating to choose your new air conditioner? Here is an easy example.
Let's say your current air conditioner unit has a rating of SEER 10. The new AC unit you want to buy is rated SEER 15. According to this cool free SEER cost savings comparison calculator, you could save more than $600 on energy expenses in the first year alone!
Furnace Efficiency Ratings
For a furnace, the unit of measurement to look for is AFUE, or Annual Fuel Utilization Efficiency. AFUE is measured through percentages and their ratings can go all the way up to 98 percent.
Here in Canada, the requirements for minimum AFUE rating are different depending on what type of fuel your new furnace uses. For oil furnaces, the minimum AFUE is 78 percent. For gas furnaces (non-weatherized), the minimum AFUE is 90 percent.
How can you use the AFUE rating to choose your new furnace? Here is an easy example.
Let's say you are looking at a new furnace with an AFUE rating of 95 percent. Under ideal conditions, this basically means that for every one dollar of fuel input, 95 cents of that will be turned into heat.
You might also enjoy playing around with this cool free calculator that helps you estimate your energy bill savings based on the AFUE rating of your current furnace versus your new furnace.
How Much Efficiency Do You Really Require?
In the wake of the ongoing pandemic, we've spent the last 12 months answering questions from anxious customers about HVAC efficiency as it relates to indoor air quality.
But the truth is, choosing an air conditioner or furnace with a higher efficiency rating will not necessarily translate into better indoor air quality. In addition, higher efficiency will not necessarily trim your energy costs - not unless some additional requirements are also met.
The better strategy is to choose the HVAC equipment with the efficiency rating that best matches each of the following:
- Your overall heating and air conditioning requirements (size of the space).
- Installation type (open/vented or closed/sealed).
- Installation location (attic, crawl space, basement, etc).
- Output type (single stage, two-stage, modulating).
- Airflow options (on/off or variable).
Choose the wrong configuration for your space and you could wind up with increasing energy costs and expensive home repairs.
Here is an example...
Let's say you choose a high efficiency furnace and you plan to use your chimney as the exhaust vent. But that high efficiency furnace exhausts pure steam, which travels up your chimney and turns into....ice. The ice seals over the chimney and triggers the furnace's safety shut-off. So now here you are in the middle of winter and you have a brand-new high efficiency furnace that won't heat.
There are several things you can do to prevent this from happening, from installing a new chimney liner to choosing your furnace fuel type (oil or natural gas versus propane, for example) carefully.
You can also opt for a lower-efficiency furnace that exhausts more of the fuel as smoke versus steam and poses less risk of an iced-over exhaust vent in severely cold weather.
This is just one example of the types of factors you will need to think through before deciding to upgrade to a higher efficiency HVAC system.
Other HVAC Features That Influence Efficiency and Energy Savings
If this hasn't already given you enough to think through, here are additional features you need to know about that can influence overall energy efficiency and impact your bottom line.
Air Conditioner Features:
- Fan-only switch and automatic delay fan switch.
- Thermal expansion valve.
- Variable speed air handler.
- Two stage compressor operation.
- Opt for an electronic ignition versus continual pilot light.
- Additional heat exchanger for heat recycling.
- Smaller flue pipe for better heat retention.
- Sealed combustion chamber.
Shipton’s Heating and Cooling Serves your HVAC needs in Burlington, Oakville, Hamilton and surrounding areas!
Shipton's has served nearly 100 years in residential and commercial customers in Oakville, Burlington and Hamilton areas. Our expert service technicians install, service and repair all makes and models of HVAC equipment.
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