For a number of years we quoted over the phone and did on-site surveys, we found the latter to be more effective when we changed our tactics slightly

When your faced with the customer you have to sell yourself, sell your company, say how good you are, say you use good equipment etc but sometimes it's very difficult for a custy to take onboard all the info.,,,,,, so
......we compiled an A4 glossy logod folder to leave with the customer...
Inside contains photos of our work, our equipment, our staff, services we provide (as we dont just clean carpets), references, corporate bodies we've worked for, certificates of insurance, cleaning guide, our cleaning method, terms, business cards, flyers, discount vouchers, referral discount scheme,. maintenance programme scheme, treatments, what have I missed out??? O yes, a hand written copy of the quote....
This works, the customer can then sit down and look through your booklet and see that you are a professional company offering a professional service.
Try it, give it a go and I bet you increase your conversions, we did!