Dear Jim: At a home show, I saw some beautiful attached sunroom-greenhouse kits. They are out of my budget, but I would like to try to build one from scratch myself. What are some of the key factors to consider? – Tonya F.

Dear Tonya: By the term “sunroom-greenhouse”, I assume you plan to use it for both living space and some gardening. Container gardening can be productive while still leaving space for a few comfortable chairs and a TV.

Before you totally write off pre-made kits, consider some of the less expensive modular ones. They often have aluminum frames and low-cost clear acrylic glazing. As your budget allows, you can add on more bays or modules.

If you plan to build a sunroom-greenhouse yourself using lumber, expect to spend a minimum of $500 for the materials. Locate the door, windows, vents, fans, etc. in one end or in the front. This leaves one simple end for expansion at a later time when your budget allows.

High humidity and temperature variations are concerns. Use pressure-treated lumber throughout and paint or stain all the surfaces of each piece after it is cut to size. Don’t forget the cut ends. This increases the overall construction time for the project unless you can cut and paint all the frame members at one time.

To minimize material costs, design your sunroom-greenhouse in multiples of 4 feet. Since most lumber is available in 8-foot lengths, this reduces waste. Check at your home center or building supply outlets for any pieces of discounted scratched acrylic. You can locate a vent or door in the damaged area.

In the design phase, consider how you plan to use it. If you are using it primarily for living space, you will get the most usable floor space and headroom with a vertical clear front wall. Glazing only part of the roof is good to provide enough light for a few plants and shade for occupants.

A lean-to design with a completely slanted front or a low knee wall is simpler to build and reduces the material costs since less roofing is needed. This design is ideal for mainly growing plants with a smaller living space. Its main drawback is that, with a slanted front, it tends to overheat.

If you are planning to grow plants year-round or use it to provide some free passive heat for your home in the winter, true solar south is the best orientation. Check with your local weather service because solar south varies from compass south. An orientation within 15 degrees to either side of south is acceptable.

Plan on using a brick, stone or concrete floor for thermal mass. Without it, it surely will get uncomfortably hot in the summer and not stay warm in the winter. Decoratively painted barrels, filled with water, also work well.

Write for (or instantly download – www.dulley.com) Update Bulletin No. 529 – do-it-yourself instructions, diagrams, and materials list to build a low-cost sunroom-greenhouse and a cold frame, a thermal mass chart and a common greenhouse plants growing guide. Please include $3 and a business-size SASE and send to James Dulley, Bangor Daily News, 6906 Royalgreen Dr., Cincinnati, Ohio 45244

Dear Jim: I have heard of window air conditioners that can both heat and cool a room. Are they much bigger than standard window units and do they heat very efficiently? – Jon F.

Dear Jon: Almost all major window air conditioner manufacturers also offer units that heat as well as cool. They are the identical size to standard units and you cannot tell one from a cool-only unit by sight. The heat is provided by either a heat pump or electrical resistance heating strips inside it. The heat pump models will heat about three times more efficiently than ones with less expensive resistance heat strips.