It could be against the house. But it does need full sun. South facing would be best.
You could grow tomatoes in the winter but they would be expensive tomatoes. Not only would you need heat but you may need supplemental lighting. But alot of people feel it's worth it
HF does have them on sale for $299. sometimes.
Here is a site with helpful information.
Read all the information on resources,
Site location, heating and cooling requirements and ventilation.
You will need to allow several hundred extra dollars for equipment. Fans (exhaust and circulation), shutter, water and electrical hookups and heating.
You could probally get by with two 1500watt heaters from Wal-mart for around $20 each. Your exhaust fan and shutter will probally be the most expensive item.
If you want to use it in the winter a solar pool cover will offer the best insulation. You could use ordinary bubble wrap but it will only last one season. Greenhouse bubble wrap cost as much as the solar cover and the solar cover is thicker, more durable and comes in one large piece making it easier to handle.

Here is a link that might be useful: Greenhouse information

I have a HFGH and as Cactusfreak says the extras are what cost . I live in NY and 2 heaters keep my GH at 55 degree in 0 degree weather. I used bubble wrap on the inside.

A small GH is harder to keep cool and in your climate that will probably be the main issue. You will need an autovent opener($35.00 at http://www.hydro-gardens.com/cooling_&_ventilation.htm#Univent ). The cheapest exhaust fan I could find was at http://www.ventilationdirect.com/catalog/fanCatalog.asp?catId=120 and that goes for $81.50 plus ship (or take a box fan apart and mount that if you are clever) and it has to be wired into your electic perferable to a thermostat.You will need circulation fans inside but they are cheap, Walmart for $5.00 apiece, I have 3.

I have a wireless therm., one in GH and one in house so I know the temp in GH without running outside in the cold( $20.00 at walmart).You can buy a shutter for about $40.00. Don't forget a shade cloth, which for HFGH its about $75.00.

I have water hookups in mine, better than dragging water and misting the plants and wetting the floor helps to cool the GH down. You also have the foundation to purchase plus shelving. I think I spent about $175.00 for those. My DH ran the electric and the water so I saved on paying for that.

As far as tomatoes, tomatoes lose their flavor if they don't get the proper amount of light so you would have to have lights to get a good tomato.

I am certainly not trying to paint a bad picture but the cost mount up. Every penny I spent and still spending is well worth it to me. I love my HFGH and wouldn't live without it but if you are asking for the real cost, this is a guide to go by.

Good luck talking your DH into buying a GH. Hopes this helps, and of course this just what I have experienced.

You know after reading these, and owning a HFGH, I say spend the money like I did and garden indoors with a 400w HID sodium light, or metal halide, and a basic hydroponic system, you can get tons of veggies,lettuce,herbs, even those winter tomatoes. It is so much easier that formulating all of these GH variables.

I may never trust my neighbors and the weather enough to move all of my hydro systems, lights, and temp/ humidity controllers into the HFGH. It isn't a very secure little structure.

I say spend about $350-400 bucks on lights, then get a basic hydroponic system, maybe 4-6 sites or so for more options. Check out the "Hydroponics" forum for more of the easiest gardening you'll ever do.

-Jason

Hi Jason. That is very interesting. I am short on space in the house with five kids but I think I will pop over and get a little educated.

Hi Willow. Thank you so much for the cost estimates. Whew! I really need to think this over! It sure seems like fun though!

All:
I just finished installing my HFGH with water and electric hookups. It's on the south side of the house. However, I recently noticed that now that the sun is a lot lower, it is blocked by my tall pine trees. So I do not get much sun in the winter. I did not have that problem in the summer since the sun is a lot higher. Bummer. Very poor planning and thinking on my part.

Any idea I should do other than moving the GH or chop down the trees? Neither is really an option.

Sign up on Harbor Freight for their emails and you will get a 20% off certificate. We got ours on sale at $299 plus used the 20% cert. and bought it in a part of the state where we only paid 3% sales tax.

Ken & Sue in GLassboro, NJ

I have a bare bones HFGH - no electricity, no heat, no lights, no fan. Here in the Sierra's it gets into the low 20s at night. The winter crops, like broccoli, cauliflower, lettuce, onions, & snow peas do great in it! The GH basically keeps the frost burn off of the plants. I suppose if it gets really cold I could add a layer of plastic over the plants for more protection but so far I have not done this. I think part of the reason the plants don't freeze is that I have cement pavers on the floor that probably get some heat gain during the day and I'm pretty sure the Earthboxes, which are dark green, heat the soil for further heat gain.

I have very limited space because I'm on a hill. The only flat spot is my dam, which is about 12' wide on top. I've got 2 HFGH in a row with a little outside garden in between. The HFGHs are perfect for that spot! I put 7 Earthboxes in each GH. The E-boxes let me pack a huge amount of veggies into a very small space. Right now I have 42 broc/cauliflowers, 6 tomato plants, 2 cucumber, 1 box strawberries, 1 box onions, 1 box lettuce, 3 bell pepper. I'm also srouting snow peas to plant.

The tomato plants have filled one GH to the rafters. There is crawling space only in that GH! Pretty soon I'll take out the tomatoes & plant the peas.