Everything You Always Wanted to Know About Boilers and Furnaces but Were Afraid to Ask

Pop quiz: What’s the difference between boilers and furnaces?

If you’re not sure, join the club. We regularly get phone calls from homeowners seeking help with their heating systems, but often they can’t tell us if they’re using a boiler, furnace, or hamster wheel. While there’s no shame in not knowing, there’s real incentive to understand your home’s heating system: you will know how to properly maintain it, how to ask for professional help, and how to avoid any mid-winter emergencies that turn your living room into a walk-in freezer. In this article, we’ll show you the differences between boilers and furnaces, explain filters and MERV ratings, and offer advice for how to properly maintain your home’s heating system.

Do I have a boiler?

How to know you have a boiler: Your home has radiant floor heat, hydronic baseboard heaters, or radiators.

A boiler system, also known as a hydronic heat system, uses a combustion source (natural gas, propane, or fuel oil) to heat water, which then runs through the pipes in your home to keep you warm. Because heat rises, the pipes containing this hot water are usually located under the floor. In this way, heat is evenly distributed throughout your home, making a boiler system a comfortable and efficient source of heat. 

What you might not know about your boiler: Boiler systems require 24 hours to fully heat your home. So if cold weather is coming, turn up your thermostat earlier than you need it!


Do I have a furnace?

How to know you have a furnace: Your home has air vents.

A furnace system heats air and blows it through the ventilation in your home. The air movement of a furnace system heats less evenly than a boiler system, resulting in hot and cold spots in your home. (Though this draftiness can be nice to have during the summer.)

What you might not know about your furnace: This is one of the biggest differences between boilers and furnaces: while a boiler doesn’t have a filter, a furnace does. So you will need to check your filter regularly to ensure clean air is circulating through your home. Need filter help? Keep reading: we’ll break it down for you.


Furnace users: know your filter

An air filter’s job is to keep particle-heavy air from getting into the furnace system, which results in a well-running furnace and cleaner air circulating through your home. If you live near dirt roads, in a house with pets, or on a property with livestock, maintaining your furnace’s filter is essential for the health of your heating system — and, ultimately, your own.

A quick word on MERV rating

MERV, or Minimum Efficiency Reporting Value, measures the effectiveness of your air filter. The MERV rating ranges from 1 to 16; the higher the number, the better your filter prevents air particles from passing through. Ratings between 7 to 12 are usually sufficient for maintaining clean air in your home. Filters with higher MERV ratings trap more particles, which requires them to be replaced more often.

Filter type: polyester, pleated, and electrostatic

Polyester filters are your cheapest — and worst — option for maintaining a clean furnace. In short, you get what you pay for: polyester is much less durable than pleated or electrostatic, which means you’ll have to replace these low-quality filters every few weeks. They are also much less effective at their main job — filtering air — putting your furnace at risk of failure and contaminating your home with unwanted air particles. The moral of this story: forget polyester, and consider the next two options. 

Pleated filters are a higher-quality disposable option for your furnace. Their accordion shape makes these filters more durable and effective than their polyester counterparts. How often you must replace your pleated filter depends on its size:

  • 1 inches: replace monthly
  • 2 inches: replace quarterly
  • 4 inches: replace every spring and fall

Electrostatic filters use static electricity to trap air particles before they enter the furnace. Unlike poly or pleated, most electrostatic filters are permanent. Because they are expected to last, these come at with the most upfront cost. While you will not have to replace you electrostatic filter, you will be expected to wash it regularly, usually about every four weeks. These filters come in sizes between 6 and 8 inches.

Schedule annual maintenance!

To ensure you are prepared for the winter, we highly recommend annual maintenance for your entire heating system. Book an appointment with an expert at the end of summer or beginning of fall, before the cold season arrives — if there are any problems to your heating system, you’ll be glad to discover them before it becomes an emergency.

If you have a furnace, we also recommend a springtime check-up. Why? Furnaces are powered in the same way as your cooling system: with freon. Freon powers your heat pumps during winter, but you cannot check these until the weather warms up. This is not something you can check yourself, so scheduling springtime maintenance will ensure the health of both your heating and cooling systems.

Final notes

Seal, seal, seal 

We can’t preach this enough: an efficient heating system won’t matter if your home’s insulation isn’t efficient. Bottom line, if you properly weatherize your home, you will lay the essential foundation for efficiently heating it.

Battery check

This is simple, yet easy to forget: remember to change the batteries to your thermostat.

If you have any further questions about the differences between boilers and furnaces — or if you need to schedule an appointment for your boiler or furnace — don’t hesitate to reach out to us.

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