What does a Garden Gnome do when she is not gardening, in the kitchen or doing genealogy? Well the answer might just surprise you so read the entries to find out more. This blog focuses on everything we do to make our house a home. There will be a strong emphasis on home energy efficiency and do-it-yourself (DIY) projects. At the same time there will also be crafts, knitting and crocheting projects along with any other little tips we do to create that down to earth, I want to be here home. Please enjoy your visit :)

Thursday, July 19, 2007

Replacing An Old Central Air Conditioner

There are several things to consider when replacing and old central air conditioner unit. In our last two houses we had old units with freon as a refrigerant. However, despite having minor leaks we were told to continue using the air conditioner unit until it finally quit. Given the age of both, I'm sure this wouldn't have take very long. We knew before we move into this house that the old air conditioner unit did not work and would need replacing. That gave me a little time to do research on central air conditioner units before the actual move.

Note: We are quite competent DIYers but I would not consider installing a central air conditioner unit a do-it-yourself project. This is one we left to the professionals. Our installation took about 5 hours with them doing it and at least we can rest easy knowing it was installed properly.


I'm usually very careful to take before and after pictures of any renovations we do. The air conditioner installers arrived just after 8 am yesterday morning. After a few long days of painting, unpacking and organizing I had completely forgotten to take before pictures.

The old unit was set in the corner between the front porch and house (1). I didn't even think to check for the brand or model number but the installers said it was as old as the furnace that was installed in 1983. The furnace will be our next major replacement but again we have been told to use it until it no longer works. With our luck that will be about mid-winter! As you can see, the old unit (2) while in still fairly good physical condition is quite old. It did not work and has not worked for the past 15 years. When it stopped working in 1992 the previous owners decided against a repair opting instead to use a couple of window air conditioners. The evapourating coil (3) is larger than the new one. Freon, and environmentally unfriendly refrigerated was the coolant.


We settled on a Carirer® Comfort Series with Puron® Refrigerant Model 24ACA (1) for reasons I will discuss further. This unit qualified for a $50 rebate from the company but not our provincial rebate. The unit that did would have cost us $500 more for a $350 rebate but based on our usage and space limitations, it wasn't feasible. Carrier was the first company to use this environmentally friendly, energy efficient refrigerant that won't deplete the ozone layer. We had the following criteria:

  1. environmentally friendly
  2. energy efficiency
  3. size restriction
  4. effectiveness
  5. quiet operation
  6. cost
Air conditioner energy efficiency is measured by SEER, the Seasonal Energy Efficiency Ratio. SEER indicates the relative amount of energy to operate provide a specific cooling output. Had the existing unit been operational it likely would have been about a SEER of 7.0. The new unit is a SEER 13.0 giving at least a 30% savings over the cooling season. We could have gone to a higher SEER rating but were restricted by location. The more efficient units are larger and for our use did not warrant the additional costs. Based on your location and usage and higher SEER rating may be desireable.

Our house is earth bermed on the lower level making that level a fairly consistent temperature. The house is well shaded from afternoon sun almost to a fault. We are also on the water so get the cooling effect from that. A good portion of our cooling is through the earth berm, shading, water and ceiling fans. So in terms of cooling, we could go with a lower SEER unit given that it will only be running a few days a month early June to mid September. We've estimated the unit will run about 21 days per cooling season. However, we live in a very humid area so when the temperature soars it can get quite uncomfortable. Our previous house cost approximately $350 to cool for the season without an earth berm, very limited afternoon shading and massive windows resulting in a lot of solar gain. Projected cooling costs for this cooling season is about $120 or less.

The new evapourator coil (2) is a bit smaller but higher than the old one so the furnace had to be modified (3). Once the coil was installed in the furnace, the installer cut a custom made door. When we replace the furnace the duct work will be modified to fit but the coil won't need to be replaced. The new air conditioner unit fits in the old spot perfectly (4). It is a bit quieter than the older models we've had but I don't think by a lot. I trimmed back the boxwood shrub on the side closest to the unit. While the installers said that shouldn't be necessary, one of them said a 10" clearance around the unit was desirable so I did so. Anything that impedes the air flow will result in lowered energy efficiency.

As part of the installation an energy efficient, programmable thermostat was installed (not shown). There was a $50 rebate on the thermostat even though it is stamped with the company's logo with no other documentation. Total cost was $2,980 CDN less $100 in rebates including full installation. Installation included the removal and disposal of existing equipment and re-installation in the same location, re-connection or revision of gas piping, electrical and venting system along with necessary duct work modification. It also included new copper lines and 'A' coil. I would have liked to see a little discount for paying upon invoicing that I assume to be 30 days even though I wanted to pay upon installation. Their installers are not allowed to accept payment which I don't really understand and we have to pay either cash, money order or cheque as credit card payments have a 2% surcharge. At any rate the price was well within our budget. We were very pleased with the quality of the installation as well so will be recommending this firm to our friends.

Stay tuned tomorrow to learn about our fun with electricity!

Garden Gnome
© 2007


Jeremy said...

Glad to see people begin to grasp the phase out of R-22. R410A is a great product and I sold it for many years simply on it's future enviromental impact.

Did you change the furnace at the same time?

Garden Gnome said...

Hi Jeremy, no we only changed out the AC but know we will have to replace the furnace likely within the next couple of years. The furnace is a Clare Megasave that reported is working nicely. Given some of the other things we have found here it might have to be replaced when we start using it in October so have planned accordingly. The manufacturer for Clare went bankrupt in 1992 so parts are very difficult to find and at its age the furnace itself is not near as efficient as newer models. That being said the AC installers said to use the furnace until it dies then replace with an ultra high efficiency one. It will be the same installers so at least they know what they are dealing with. The nice thing about this company is the old metal is kept out of the landfill by recycling.

Jeremy said...

With the price of steel and copper, almost all contractors are recycling their old equipment. You made a sound choice and in a northern market a high efficiency two stage furnace will lend to great utility savings.

Mikes said...

It is very difficult sometimes to replace the central air conditioner easily. You must call a professional when you are doing that.

Garden Gnome said...

Hi Mike and thanks for visiting. If you check the post again you will see a note in red where it says we left the installation to a professional and that we did not consider this a DIY project.

mastercleanse01 said...

I think it is better to use a portable air conditioning unit this suggestion is appropriate for those who have a smaller type house.

Garden Gnome said...

Hi mastercleans01 and thanks for visiting. A portable air conditioner unit is less effect and not as energy efficient as central AC. It is extremely important to use cooling equipment that is EnergyStar rated to reduce energy consumption.

Dorothy said...


Well, there could have been a technology for central air conditioner that is energy efficient. But cannot tell which Brand is offering such technology.

Warm Regards,