Three Most Common Mistakes Made by Geothermal Designers

If you’re new to the geothermal heat pump industry, read the Geothermal 101 Reading list. It has free tools and articles on geothermal design and installation, and sales and marketing best practices.

Working in the ground source heat pump (GSHP) industry, especially in a small company where you are asked to take on the role of salesman and designer, you will find yourself answering the same questions with each new customer.  Get used to it.  If you work in the industry long enough, you will be asked every question under the sun.  How will this system heat my home when the soil temperatures are only 50 degrees?  What if I want to keep it warmer in my house?  Do I need to buy an air conditioner too?  How does a heat pump work?  The list goes on and on.

The truth is, the average homeowner doesn’t understand how their central air conditioner works (or the refrigerator in their kitchen for that matter).  They just know it works.  When you mention the term “geothermal heat pump” or “ground source heat pump” to your prospective customer, all of a sudden you find yourself in uncharted territory.  Then the questions begin.

Homeowners ask these questions because they want to understand what they are getting for their extra dollar.  You are asking them to spend a lot more of their hard earned money than they would have to spend on a conventional heating and cooling system.  Because of the price tag, the homeowner will ask questions to get comfortable with the idea of purchasing such a system, that they aren’t buying into some new fad that will be here and gone before they know it.  Most importantly, they want to get the sense that you know what you are talking about and that they can trust you with their money, especially when they are spending it on something they don’t completely understand.  These systems are a complete unknown to a vast majority of people, although that is changing.

Even if you are able to land the big sale, an improperly designed or installed system can be huge detriment to your company (and to our small industry as a whole).  Most experienced contractors and designers have made their mistakes, learned from them and moved on.  But everyone needs to start somewhere.  An expert in anything was a beginner in that subject at one point in time.  This article is intended for those who are just starting out.

In my opinion, three of the biggest mistakes that a new designer can make are

1. Underestimating the importance of accurate peak heating and cooling load calculations
2. Not giving proper consideration to the many options that are available and
3. Overcomplicating matters.

Let’s look at number one right now.

Underestimating the importance of accurate load calculations

If you’re involved in this industry in any way, you already know that the biggest hurdle we must overcome is the up-front cost associated with GSHP systems.  Because of this, we need to be accurate when sizing and selecting equipment.

It is not uncommon to see a natural gas-fired furnace with a 60,000 Btu/hr output rating down in the mechanical room when a mere 30,000 Btu/hr heating output is required.  The thing is, it really doesn’t cost that much extra to install a furnace that is twice the size it needs to be.

The price difference between putting a 30,000 Btu/hr furnace and a 60,000 Btu/hr furnace is probably a few hundred dollars.  Because of this, it is common practice to size conventional HVAC equipment based on rule of thumb principles.  Such principles minimize the amount of up-front time and investment on the part of the contractor to size and select the equipment while still being able to install a system that will serve its purpose.

If you install a 5-ton unit coupled with a “5-ton” ground heat exchanger where only 2.5 tons is required, the installation cost will be much higher than necessary.  Severe heat pump oversizing can cause a number of issues related to comfort, efficiency and equipment life expectancy, but the main concern is the fact that the customer will be paying much more for the system than necessary, which will dramatically affect the payback period on their investment.

Even if you’re able to sell a grossly oversized system, you might say, “No big deal, I was able to sell a larger system than necessary.  My bottom line looks pretty good”.  But when the homeowner realizes they aren’t as comfortable as they were hoping for and they aren’t recouping their initial investment as quickly as they were promised, they’ll tell their friends that geothermal isn’t all it’s cracked up to be.  The same goes for severely undersized systems.

Properly sizing equipment to deliver maximum performance and occupant comfort while keeping costs in check is the only way to keep our industry moving in the right direction.  The importance of high quality and great value cannot be stressed enough.  If you stick to the principles of proper system design, it’s unlikely that you’ll ever be the cheapest bidder but I guarantee that many homeowners will choose quality over price.  It is your job to inform them of the value you bring to the table that the other guys don’t.