I think they mean 5 rooms, not 5 bedrooms.....one master bedroom and 2 bedrooms for children with twin beds or bunk beds in each. I lived in a 1,300 sq ft house for 2 yrs with my husband and 2 sons. My suggestion would be to have an open floor plan for the kitchen, dining area and family room in one large room. Add a bar in the kitchen for casual dining. Be sure to include storage in family room for toys, games, etc. Add a built in desk in eiher the kitchen or family room areas . The master bedroom and bath should be large enough to accomodate a queen size bed and if possible a sitting area (maybe a bay window large enough for for a small loveseat or a couple of comfortable chairs). I would recommend a large walkin shower but no tub for the master bath. Instead have a nice size tub/ shower combo in the hall bath. Too make your house feel larger, use neutral camel, beige, gold or grey paint and carpet through out the kitchen, dining area, family, hallways and hallbath. If you want to add color, limit it to 3 bedrooms. Hanging all your window treatments at ceiling height will make your rooms feel larger and taller.

Please don't forget you must have really good drains for this extra water load. Have you considered a tankless water heater? Or at least a separate water heater for the master so that the rest if the household still has a hot water supply and pressure balance. That's something to consider also. I've often wondered, I must admit, how all of this is supposed to work with energy saving measures in place.

I agree with divadeva. More lights. If you can add pot lights do it. If they're already there add task lighting and up the wattage on the bulbs on the pot lights (replace with LED and you can make them brighter because the wattage on LED is lower for brighter light). If you have all of that add decorative lighting. If ventilation is an issue find a way to move the air around or add air filtration. Maybe the HVAC is deficient. Maybe you can add a HEPA filter instead of the standard one that comes with the unit. Call an HVAC specialist to see if there is a way to boost air flow in the room.

Hello Sagar, This space is sufficient for a bathtub in a bath. Thanks, Nitin CORNERSTONE DESIGNS, Bangalore