The qualifications of the geo contractor are very important. In the electrical world permits and licenses are clearly defined. In the plumbing world permits and licenses are clearly defined. In the hvac world it’s the Wild West. What are the qualifications of your low bid geo contractor? Is he a member of the CGC (Canadian Geoexchange Coalition)? Does he know what CSA 448 is?
The CGC develops training and standards for the advancement of geoexchange technology in Canada (and contributes to the rest of the world too). Your contractor should be a member of the CGC. If he isn’t, why not? Membership demonstrates that he is willing to be accountable to his peers and his clients. What trade qualifications do his employees have? Are they CGC certified?