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.

Old

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.

New

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
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