Wednesday, September 4, 2013

The hunt for "Net Zero" construction just got a big new gun.

As a building science nerd NZ (Net Zero) construction is the ultimate in new home construction. In full disclosure I am not only a building science nerd but I am also an advocate for geothermal heating and cooling. I have been in HVAC most of my life and I have found that nothing comes close to the comfort and efficiency you can get from a properly designed and installed geo system. With as much as 70% of a home’s power consumption coming from heating, cooling and hot water generation, few HVAC systems can come close to matching geothermal for energy savings. In further discloser I have primarily worked with WaterFurnace geothermal systems and I have always been very proud of that affiliation, in my opinion WaterFurnace has always lead the geo industry in innovation and quality. That being said, the industry is constantly evolving and it would be short sighted for me or anyone else to limit themselves to one brand of equipment.

Last year’s release of the WaterFurnace 7 series with its variable speed DC powered compressor set the new industry standard for what high efficiency geothermal could be. By varying the speed of the compressor from20% to 100% the 7 series’ ability to closely match the homes BTU needs throughout the entire heating and cooling season allowed the system to only use the power that the space required, in short the 7 series is a monumental jump in efficiency because there is little to no wasted effort do to short cycling and its DC power supply allows for a soft start eliminating the high power draw at start up. I am a huge fan of this system with over 30 -7 series installed for customers in Central KY in the last year I’ve seen nothing short of incredible energy savings. The ability to slow the compressor down to 20% capacity encourages the system to run for long durations almost acting as a whole house dehumidifier in cooling and closely resembling a radiant style heating system in the winter. It conditions the space with such a low air volume that in most cases you do not even realize that it is even running. With an impressive 550 watts of power ( that includes the fan and flow center for you geo naysayers) for low stage on the 3 ton model , you can heat and cool your home for less power than the standard coffee maker uses. Another benefit to this system is the ability to generate hot water any time the system is heating or cooling, all of this run time helps to greatly assist the home’s hot water heater and offsets its energy consumption, that 550 watts is offset by the fact that it is keeping the hot water heater from using 5000 watts to heat the water. 

So the WaterFurnace 7 series is pretty impressive and should be considered by anyone looking for the best, most efficient HVAC system for existing, new and even Net Zero construction? Yes, but it has one major shortcoming, the 7 series does you no good when you do not have a heating or cooling load. I’m sure you might be thinking “Duh! No heating and cooling system can benefit you when it’s not running right?”

Wrong! Enter the new Climatemaster Trilogy geothermal system, it heats, it cools and it provides hot water, all with a super-efficient DC powered variable speed compressor much like the waterFurnace 7 series.. Ok, so every geo on the market does this, why is this one so special? Because the Trilogy system is not just a geothermal heating and cooling system it is also a very creative geothermal heat pump hot water heater! Climatemaster has paired the Trilogy with a super insulated electric water heater called the Marathon by Rheem. The geo controls all heating, cooling and hot water generation and only allows the water heater’s heating elements to come on when the geo cannot recover quickly enough, much like emergency heat on a conventional heat pump. What makes this unique is that the geo compressor can run only to heat the water regardless of a call for heating or cooling.

This satisfies a huge need in the high efficiency home market because guess what, high efficiency super insulated homes have a very low heating and cooling load. The best geo on the market cannot help you if it’s not running, the Trilogy can by heating the hot water replacing a 5000 watt heating element with a 550 watt (guessing based on my experience with WaterFurnace because the Trilogy’s specs are not out yet) geothermal heat pump water heater. 

As we get closer to practical Net Zero construction, super insulated is becoming the norm, this lowers the heating and cooling load making hot water generation a larger percentage of the homes overall power consumption. The Climatemaster Trilogy is the first HVAC system on the market to take this into consideration and at first glance it does it very well. The Trilogy is still in field testing mode and is not yet available on the open market so it is yet to be seen if it can live up to the hype in a real world setting.

 I will say I have some concerns about all the different moving parts and pieces that have to line up for the Trilogy to function properly. It will be critical that the crew installing the Trilogy follow the installation guidelines to the letter as any deviation from the factory specifications will result in lost efficiency. That being said, in the hands of a qualified HVAC contractor the Trilogy will be a game changer for Net Zero construction.

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