I started the renovation of This Old House by considering its energy usage. An energy audit was performed early on, and I have replaced the old boiler and asbestos-clad pipes, and last summer I started investigating the replacement of the window air conditioners, ancient behemoths that consumed vast amounts of electricity, frequently blowing fuses, but providing very little cooling for all their effort.
But other renovation activities took priority, including the installation of the new boiler in August, safely in time for the fall heating season (which didn’t actually arrive until almost December). In addition, the upper floor air conditioner was removed and replaced by a new window. Knowing that the asphalt-clad mansard roof was an efficient solar heat collector, often making the upper level uncomfortably warm, I grew concerned about providing a way to remove that heat.
One of the trucks delivering parts and workers to install the AC.
I selected a heating and air conditioning contractor to install a new technology for air conditioning known as “mini-splits”. In a typical central air conditioning system, there is an outside compressor unit that removes heat from a coolant, which is then sent to a central place to cool the inside air, which is then forced through ducts to the various rooms in the house.
A mini-split system does not use a central forced air distribution system. There is still an outside compressor, but instead, it sends multiple lines of coolant (the mini splits?) to local room heat exchangers. In my case there are three such cooling heads: two on the main floor, and one larger unit to cool the more open upper floor. The heads are each on their own individual thermostats, calling for coolant only when needed. They respond to hand-held remote controls that tell them the desired temperature, fan speeds, scheduling, etc. They even have heat-sensing eyes that survey the room and determine where to aim their fan vents!
I am told that these are the highest efficiency systems available for cooling, but unlike some of the other energy sinks in a house, there are no incentives or rebates for them (I received utility rebates and tax credits for the high efficiency boiler). I expect my electricity costs to be lower this summer. I don’t really expect to live long enough to amortize this system, but it was the morally right thing to do.
The HVAC company expected to install the system in one day. As usual, This Odd House put up some resistance. In particular, drilling through the 1-1/2 foot foundation to run the coolant and control lines was a problem. In one location, the masonry drills were used to their full 2-foot depth without penetrating the inner wall. A new location was selected for the hole.
The drill went in as far as it could go, but did not emerge on the inside wall. I speculate that it was drilling into the side foundation wall (1-1/2 foot thick).
Other setbacks caused the installation to spill into a second day, May 2. During this day, a snowstorm blanketed the city and temperatures plunged below freezing. Air conditioner technicians were outside performing cooling system tests and measuring Freon-equivalent coolant quantities.
Pressure test preparation.
Air conditioning compressor, ready and waiting for the May snowstorms to retreat.
We have experienced this weather over the entire month of April, and it is continuing. I was concerned about getting the cooling system in before spring, but since spring has been cancelled, the urgency is gone.
Instead, on the day my new air conditioning system was installed, I found myself learning the remote control buttons to switch the heat pump direction into reverse, and enjoying the warm air that spilled into the bedroom on a cold May evening.