10Q's for New HVAC in Old House

[ngribas]

Background:
We have a 100-yr old frame house with 1,700sf on two stories plus an attic and a basement near the ocean
in the near future (1 to yrs) we'd like to use the basement and the attic each about 700 usable sf
The walls of the house are plastered and we believe that they’re not insulated
The house has water-heated radiators that respond very well and heat up the house quickly, there is one thermostat on the first floor

Challenges:
The basement is a bit damp and especially in the summer it gets musty and has an odor
There is lack of hot water after 2 showers
The house is too dry on the 2nd floor in the winter

Goals:
We’d like to air condition the house (we're getting recommendations fro a 2 ton for 1st and 2.5 to 3 ton for 2nd floor)
We’d like to solve the lack of hot water
Monitor the lack of humidity during winter in the 2nd floor
Monitor the humidity in the basement

Design choices:
(1) Should we replace the radiators? And use existing boiler
(2) Should we go with two traditional HVAC units with air handlers located in basement for the 1st floor feeding from the floor, and attic for the 2nd floor feeding from the ceiling?
(3) Should we consider hi-velocity units for this application?
(4) Should we add an 80 gal indirect domestic hot water system?
(5) Do we need humidifiers for the 1st and 2nd floor?
(6) Should we install a dehumidifier in the basement?
(7) Should we get hepa filtration?
(8) Should we get variable speed motors?
(9) Should we go with 10 or 12 seer?
(10) What else should be considered?

Thank you!

[ps]

More information is needed. I can only opine on heating issues. The more specific you can be, the more specific others can be.
1. What is the heat/cool load for the existing and expanded living areas?
2. What are the specifics on your heating and DHW system (age, condition, output, piping, etc)? How much DHW do you use?
3. Do you have any intentions on increasing insulation, drying out basement, renovating existing spaces, foundation sealing, etc?

As a general rule, you will benefit most ($, comfort) if you focus on the insulation and air/moisture infiltration issues first. While these may not eliminate your humidity problems - they should help and you do not want to add or replace your heating/cooling systems until you know what you need (via load calcs). Don't waste your $ on new A/C, boiler until you can properly size them.

Provide more info and others can help.

[ngribas]

Thank you for your prompt response.

1. What is the heat/cool load for the existing and expanded living areas?

The cooling load for the 2nd floor was determined to require a 2.5 to 3-ton AC unit.
The cooling load for the 1st floor was determined to require a 2-ton AC unit.

The house is a 4-bd, 2 stories with attic and basement, single-family, located near the ocean in the northeastern US, and it is used primarily in the summer. There are 1,000 sf on the first and 700 sf on the second floor. There are approximately 700 sf in the attic and 700 sf in the basement both will be finished in the next 1 to 2 years.

The 1st floor has kitchen, dining, living and bathroom with 18 3’x5’ windows of which 7 have southern exposure and 4 northern exposure, 2 5’x7’ patio glass doors with southern-exposure but shaded, and 1 3’x7’ door with northern exposure.

The 2nd floor has 4 bedroom and a bathroom with 11 3’x5’ windows of which 3 have southern exposure and 2 have northern exposure.

Future additions include a second bathroom on the 2nd floor with 7 3’x5’ windows with southern exposure.

The attic has 2 3’x5’ windows 1 southern and 1 northern exposure, also another 3 dorm windows will be installed when the attic is finished.

The basement is brick with about 8 1.5’x3’ windows.

The house is frame and is not insulated. The roof will be insulated.

2. What are the specifics on your heating and DHW system (age, condition, output, piping, etc)? How much DHW do you use?

The domestic hot water system includes:

a. space heating system

The space is heated by cast iron radiators. On the 1st floor there are about 5 1.5x1.5x4 units, and 5 smaller units on the 2nd.

The radiators are about 50+ years old but they respond quickly and heat the house well.

The gas-fired water heater for the radiators is relatively new.

b. water heating system

The gas-fired hot water heater is relatively new, it is about 20 gallons

The peak use of hot water would be about 4 or 5 successive showers in one hour (80 gallons?).

3. Do you have any intentions on increasing insulation, drying out basement, renovating existing spaces, foundation sealing, etc?

Yes, the insulation will be increased but only partially. The exterior walls of the bathroom (5’x8’) on the first floor are now insulated, and part of the exterior kitchen wall will be insulated. And, the attic will be insulated.

Yes, the basement does have a moisture problem, where one of its walls appears to have moisture damage and one section of its brick floor is damp. There is a possibility that both of these will be addressed. The exterior wall will be dug up from the outside and tarred. And there will be a French (or should I say, Freedom) drain installed in the perimeter of the basement floor with a sump pump.

Your suggestion that we address the moisture inflirtration problem first before we install a dehumidifier in the basement makes sense. Please comment if I understood you correctly.
We need to install air conditioning even if the house is partially insulated. At that point should we air condition the basement? Would you recommend that?

Thank you again for your comments.