Sunday, October 1, 2023

Boiler Heat for US citizens

 In the early 2010's my wife and I were looking for a good home for our lives.  While searching we found a number of homes that did not have a traditional HVAC system with a natural gas furnace and central air.  We overlooked a lot of these homes until we found one that we fell in love with.  Over the last decade we've learned a lot about boilers and at this point will probably never own a home with a traditional HVAC system.

So lets cover something straight up.  There are MANY different types of home heating and cooling systems out there currently.  The traditional furnace and air conditioner is probably one of the worst on the market.  Here's why:


  • Cheap to implement: Installs quickly.  A typical furnace and air conditioner can be swapped out in a day.
  • A total swap usually costs between $3k-$6k
  • Longevity:  Both a furnace and air conditioner have a life span of 10-15 years.
  • Humidity: Because you're heating air with a open flame all of the humidity in the air is eliminated.  This usually means you absolutely need some form of humidifier added onto your furnace.
  • Monthly expenses:  Even high efficiency furnaces are quite expensive to run.  Because you're directly heating air in your home, and even homes with the best insulation possible, you have no mass to retain that heat.  As such you're constantly burning fuel to keep your home warm in the winter.
  • Zoning:  The ability to set different temperatures in different areas of the house.  Very handy when you have some rooms that are warmer or colder than others.  You have few abilities here.  Either you open and close individual vents which doesn't help much, or you invest in an expensive shutter system or multiple furnaces and air conditioner compressors.
Now lets compare this to a Boiler.

  • Longevity:  Boilers can and do last 50 years and longer.  In many cases a boiler will be replaced because it's more economical to do so due to fuel consumed.  Parts are common plumbing parts and repairs can be done by most plumbers.
  • Humidity: Because a flame is used to heat water via a heat exchanger, and then the heated water is pumped through the home no humidity is lost.  A boiler heated home may still need additional humidity to be comfortable on the coldest days a room humidifier can usually perform the needed duty.
  • Monthly expenses:  A boiler heats water, and that water heats the home.  As you have the mass of the water and the typically copper pipe all heated you use less fuel to warm the home.  Even completely inefficient boilers will use less fuel to heat a similar home compared to a traditional high efficiency furnace.
  • Zoning: You're pumping water around your house through loops of pipes.  This is controlled with automated valves.  Simple to implement and control.  You'll rarely have issues keeping your home an even temperature.
  • Air conditioning isn't possible in the same way as a furnace based system.  Until recently a separate air handler needed to be added to the house, or you used window based AC units
  • Expense:  A boiler can cost 2x - 3x the cost of a furnace and air conditioner.
  • Install:  A boiler install is not a quick endevour.  Replacing a boiler involves a plumber and electrician and can take a week hence the massive expense over a furnace.  The boiler costs as much as the furnace.  It's all labor that makes the difference.
These numbers and experiences are based on my own experience.  Comparing two homes I've lived in at different points in my life of similar size.  One with a high efficiency furnace and the other with a 1960's no efficiency boiler and the older boiler proved to be more cost effective to run.

As for Air conditioning.  While a boiler means you don't have the familiar heat + AC system you're probably familiar with it does not mean you can't cool your home.  In existing boiler homes you'll see some of the following:

  1. Window Units / Portable AC:  These are fairly typical and cost effective.  New designs from GE and Medea mean you can now effectively leave a window AC installed year round and keep the ability to look out the window and open it.
  2. High Velocity Air Conditioning:  If you see little white circles on the ceiling of the property you're looking at the house has a central air conditioner already installed.  The unit is in the attic and pushes air through the house.  This system has fallen out of favor very recently due to advances and price drops in the mini split air conditioner systems.  If a house doesn't have this do not install it new.  The cost is high and parts are becoming hard to get.  If you already have one the only wear part is the condenser outside which is a standard part.
  3. Mini-splits:  If you've seen ads for "Mr. Cool DIY" you probably know where this is going.  This sort of air conditioner / heat pump has become very popular due to the ease in which a home owner can install it and save quite a lot of money over a traditional central AC.
Here's a scenario for you.  Lets say you're looking at a home with a very old boiler and no air conditioning.  Your inspection states that the boiler is in good working condition and will run for years to come.  You have a multiple mercury switch thermostats in the home allowing different temperatures to be set in each area.  You want a home with air conditioning and some convenience in monitoring and setting temperatures.

The solution is quite inexpensive if you're handy, and thanks to recent tax breaks for heat pumps will be even easier on your wallet.  You'll want to install a multi-head mini split unit.  Heat pump mini splits not only can cool your home, but can heat it as well.  In addition if temperatures dive below the mini split's ability to handle they can call for heat from your existing boiler as "Aux Heat".  The mercury switch thermostats are eliminated and the boiler is controlled directly by the mini split system.  As most mini splits are able to be controlled over wifi from your phone you can bring an ancient boiler into the 20'th century.  And as the mini split is highly efficient you gain the lower heating bills on all but the most extreme winter conditions.  On those days you'll fire up the old boiler.

If you're handy installing one of these kits can cost a quarter of a professionally installed central air system, and can be done in as little as a day even by an newbie.  Many YouTube videos exist on installing these units.  If money is really tight you can purchase one of the Mr. Cool competitors.  You might need a vacuum pump and a few extra tools, but you'll wind up with a better final product for less money even after buying tools.

Here's the final thought.  In todays competitive home market homes that are slightly different might wind up overlooked.  Most people want what's instantly familiar.  They don't want a home with a boiler and instead want something with a known furnace.  This means you might not have the insane bidding war on a boiler home in the same neighborhood as a furnace home.  The money you save can be easily spent to add a mini split heat pump system.  You'll wind up comfortable year round and wonder why you ever bothered with a furnace.