Out for estimates on hvac system replacement, tankless water heater install, running extra gas line to kitchen, full house repipe. Is with the addition, if design change or layouts change, so will the price. Price is good for 30 days. Once gets new plans we can adjust out price from there. Payment Terms are negotiable, Our payment schedule is usually 10% down payment, 40% progress payment mid way thru job, 40% on completion of job, 10% after final inspection. Job would take about 1 week of hvac work, 1 week of plumbing work. Could be done at same time by different crews. And then once our portions of the job are done and inspected the last payment is due.