“The Consumers Guide”
To High Efficiency Gas Boilers
Choosing the right boiler for your home or business can be confusing. Every heating contractor you talk to will tell you theirs is the best.
So, who do you believe?
To help you make an intelligent decision there are some THINGS you should know
We’ve compiled some FACTS for you to examine.
Keep in mind – these are facts based on science and physics – NOT our opinion.
The Myth of Efficiency Ratings
Heating boilers have a rating system called AFUE.
AFUE stands for Annual Fuel Utilization Efficiency.
The simple explanation for AFUE - the ratio of heat that goes into the living space vs. what is lost up the chimney.
Older heating boilers can have efficiency ratings as low as 50% while newer versions range from 83% to 95%.
In theory, if a boiler has a 90% rating, you should get 90 cents worth of heat for every dollar you pay.
But. . .
Higher ratings don’t always translate into lower fuel bills.
The rating system for boilers has many flaws because they are based on best-case, laboratory scenarios and assumptions that don’t really exist in real world applications.
In fact - many so-called high-efficiency boilers operate well below their stated efficiency because they use an inferior, out-dated control system.
Here’s why. . .
Boilers that have an AFUE rating over 90% need to operate with system water temperatures below 135 degrees in order to achieve the higher AFUE rating.
For every degree the water temperature drops below 135 degrees the efficiency INCREASES.
Conversely, for every degree the water temperature goes ABOVE 135 degrees the efficiency DECREASES.
Simply put –
The cooler the water - the more efficient the boiler
As you can see, the control system is a major factor to actual energy savings.
The typical heating cycle of a hot water system consists of 180-200 degree water circulated through a radiator or baseboard system.
Unless it is the coldest day of the year, these high water temperatures are unnecessary.
Believe it or not, at certain outdoor temperatures you can actually heat a home with 80 degree water temperatures.
Don’t Waste Your Money On A Boiler That Has An Old-Fashion Control System
Control systems are now available that adjust the water temperature according to the outdoor temperature.
As the outdoor temperature drops the boiler temperature increases.
This is called weather responsive control or outdoor reset.
Energy savings of up to 20% can be realized using this common-sense strategy if it is applied to the right boiler.
Low water temperatures and high efficiency gas condensing boilers with AFUE ratings over 90% are a perfect match.
High quality, high efficient boiler systems can cost up to twice as much as others, but you’ll recoup your investment through lower energy bills, less repairs and a longer lasting system.
There are many boilers still operating that are 80 -90 years old!
Though they may not be super-efficient, they have proven to be durable and reliable because of the amount of mass (material) in the construction of these vessels.
Compare these with today’s boilers that you can carry into a basement.
Some of these newer boilers are constructed of aluminum, however - the ones constructed of cast iron or high grade stainless steel are the best bet for longevity.
A well respected German manufacturer discontinued the use of aluminum because of the question of longevity.
What About Warranties?
Warranties on high-efficiency boilers are basically the same for all manufactures.
They offer a LIMITED Lifetime warranty on the heat exchanger (the most expensive part of the boiler).
The keyword is LIMITED.
Here are the LIMITS:
The 1st -10th years you get a replacement heat exchanger at no charge (excludes labor).
After the 11th year and beyond the heat exchanger replacement is pro-rated.
I’m not a fan of these so-called LIFETIME Warranties but as I stated above, it’s typical of the industry.
Some companies will replace the heat exchanger up to 7 years. After that it’s pro-rated to the 12th year.
After the 12th year, you are out of luck.
When comparing warranties, don’t overlook the fine print - this is where some manufacturers try to weasel their way out.
Don’t Just Replace The Boiler
Some companies just come in, cut the supply and return pipes and attach the new boiler, give you a new circulator and if you’re lucky, you’ll get a new thermostat
Our belief is;
If we go as far as removing your boiler, it just makes sense and it’s cost effective to replace all the peripheral parts that are most likely as old as the boiler, instead of nickeling and diming you, one part at a time.
We both know that Murphy’s Law will always kick in – one of those old parts will break down on one of the coldest nights of the year.
- Be sure the boiler will operate at water temperatures below 135 degrees for the majority of the heating season
- Choose the highest rated AFUE rated boiler possible
- Stainless steel is a superior material for boiler construction
- Replace all the older parts of the heating system in the mechanical room
- The lowest price boiler will always end up costing you more