Hi,

I'm in the process of deciding between installers for an oil-to-gas conversion. I will be upgrading to forced air. Any insight will be much appreciated.

The home is 2 stories (1 unit on the bottom and 1 on top). Unit 1 is 1200 sq ft and unit 2 is about 1325 sq ft. The home is built in 1930 and is located in Boston, Ma. The only additional insulation is the attic floor (rolled on pink stuff).

As it currently stand, I plan to have one furnance installed in the basement and the other in the attic. I've read how with high efficiency furnance, the condensation line may freeze since the attic is unconditioned space. Will a capable installer be able to prevent this?

Below are the quotes. I am currently thinking about going with company 3 but I have 2 more companies coming in to provide estimates. Company 3 provided J calculations, will install returns in all rooms, and will remove the old system including radiatiors. The other companies were not willing to remove radiators and said I will only need 1 central return. Company 2 said that they will only install an 80% furnance because of freeze issues.

Company 1 ($38900.00 - 5100/tax credit rebates):

Equipment: Two (2) Carrier Model 59MN7 Infinity Series Modulating Variable Speed Gas Furnace

Two (2) Carrier Model 24ANB Infinity Series 2-Stage Condenser

Two (2) Carrier CNPxP Cased Evaporator Coil

Two (2) Carrier MERV 11 4�� Pleated Air Cleaner

Two (2) Carrier Infinity Touch Control

1) Main duct to be 26 gauge galvanized steel with R-8 insulation.

2) Insulated flexible runouts to each supply air outlet and return air inlet.

3) Necessary supply air registers and return air grilles.

4) Complete gas-piping system with necessary permit.

5) Necessary chimney liner.

6) Condensate pump and piping with acid neutralizer.

7) Secondary drain pan under air handling unit.

8) Outside condensing unit support pad.

9) Necessary refrigerant piping.

10) Heating and cooling thermostat.

11) Installation of air cleaner.

12) Installation of required gas code carbon monoxide detector.

13) Removal and disposal of the existing oil boiler equipment.

14) Necessary electrical wiring.

15) Start up and check operation.

16) One year parts and labor warranty. Manufacturers extended limited lifetime warranty on the Heat Exchanger
and 10 years on the parts. Extended warranties include provisions for the replacement parts only - no labor/ freight/acc.

Company 2 ($26,939.60 - $2350 rebates/tax credit)

We will hire a removal company to remove the existing boils and oil tanks from your property.

We will cap the chimney openings that the oil boiler smoke pipes are in.

We will supply and install 1- Carrier Infinity Series variable capacity modulating 97.4% AFUE 60,000 BTU gas fired furnace model 59MN7A060V17--14.

We will supply and install 1 Carrier cooling coil model CNPVP3017V17.

We will supply and install 1- 2.0 ton 17 SEER 2 stage Carrier condenser model 24ANB724A003.

We will supply and install a sheet metal supply and return trunk. We will wrap it in R-6 valued foil faced insulation.

We will supply and install a mixture of hard pipe and flex pipe to each supply box also insulated with R-6 foil faced insulation.

We will supply and install the supply boxes and supply registers needed to properly heat and cool the 1st floor.

We will supply and install the return runs needed to give proper air flow.

We will supply and install 1 Infinity Series programmable heat/ cool/ dehumidify thermostat.

We will supply and install 1 condensate pump. We will install an acid neutralizer.

** 2nd floor scope of work:

We will supply and install 1- Carrier Infinity Series variable speed 80% AFUE 90,000 BTU gas fired furnace model

58CVA090--1--16

We will supply and install 1 Carrier cooling coil model CNPHP4321ALA.

We will supply and install 1 3.0 ton 17 SEER 2 stage Carrier condenser model 24ANB736A003.

We will flue the furnace to the outside.

We will supply and install a sheet metal supply and return trunk. We will wrap it in R-8 valued foil faced insulation.

We will supply and flex pipe to each supply box also insulated with R-8 foil faced insulation.

We will supply and install the supply boxes and supply registers needed to properly heat and cool the 2nd floor.

We will supply and install the return runs needed to give proper air flow.

We will supply and install 1 Infinity Series programmable heat/ cool/ dehumidify thermostat

We will supply and install 1 PVC condensate drain.

We will have our Massachusetts licensed electrician run a new circuit from the existing 1st floor fuse box to the condenser.

We will run a new gas pipe from the 1st floor gas meter to the new furnace as needed.

Permits and inspections are included in the price.

Company 3 ($26898 - $2710 rebates/tax credit)

Two (2) Trane XV95 Two Stage Variable Speed Gas Fired Furnaces (1) in Basement and (1) in Attic.

Two (2) Trane XB16 R-410A Split System A/C Condensers with Pads.

Two (2) Trane Aluminum Cased Evaporator A/C Coils.

All necessary insulated ductwork throughout Attic and Basement with insulated lines to each register boot both supply and returns.

All necessary wall, ceiling and floor registers for both Apartments both supply and returns.

Two (2) A/C Linesets from Indoor Coils to Outdoor Condensers.

P.V.C. venting and Air Intake to be vented outdoors for both units complete with pipe, fittings and termination.

Condensate pan, pump, float switch, P.V.C. pipe and fittings to be piped to indirect waste in Basement.

Dedicated gas lines to each Furnace from existing gas service complete with pipe, fittings, hangers and gas shut offs.

All necessary wiring to all components from each existing electrical panel and all necessary low voltage wiring including Two (2) Trane XL602 Programmable Thermostat

Remove and dispose of all boilers, piping were exposed, radiators, oil tanks and all related trash.

This post was edited by hchan1 on Tue, Aug 20, 13 at 11:05