Older model Park Models we're not made for extreme climates. Do your homework before you purchase. Find out how much insulation is in the walls. Ask about the construction. Most of the time there isn't any insulation in the ceiling. Also find notes about formaldehyde in the materials that were used to build older units. Many owners report electric bills in the summer for a 400 square foot unit climbing upwards of $800.00 per month. Often the studs used in these units were 2x2s. The space for insulation may be as little as 2.5 in inches. Older units have single pane windows. Check for aluminum wiring. Check for plastic plumbing. Do your homework.