---
title: "Home Energy Analysis"
id: 76455
type: "computer_media"
slug: "home-energy-analysis"
url: "http://localhost/computer_media/home-energy-analysis/"
markdown_url: "http://localhost/computer_media/home-energy-analysis.md"
published_at: "2026-11-11T08:02:38+00:00"
modified_at: "2026-11-11T08:02:38+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/11/home-energy-analysis-1.png"
excerpt: "Find the cost per unit, the comfort energy cost, the cost per degree day and an efficiency rating from a month's heating or cooling bill."
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
  - name: "ZX81"
    slug: "zx81"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx81/"
model:
  - name: "Sinclair ZX81"
    slug: "zx81"
    taxonomy: "model"
    url: "http://localhost/model/zx81/"
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
indiv:
  - name: "James Holder"
    slug: "james-holder"
    taxonomy: "indiv"
    url: "http://localhost/indiv/james-holder/"
genre:
  - name: "Home"
    slug: "home"
    taxonomy: "genre"
    url: "http://localhost/type/home/"
media_type: "Program"
programmers:
  - name: "James Holder"
    slug: "james-holder"
    taxonomy: "indiv"
    url: "http://localhost/indiv/james-holder/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Home%20Energy%20Analysis%20%281982%29%28Holder%2C%20James%29%28TS1000%29%28US%29%28Program%29.zip"
mediadate: "1982"
images:
  - url: "http://localhost/wp-content/uploads/2026/11/home-energy-analysis-1.png"
  - url: "http://localhost/wp-content/uploads/2026/11/home-energy-analysis-2.png"
article_media:
  - id: 19385
    title: "Home Energy Analysis"
    type: "article"
    url: "http://localhost/article/home-energy-analysis/"
media_type_tags: "Home"
license: false
---

# Home Energy Analysis

A home energy calculator. Choose A for air conditioning or H for heating, then enter the month, the cost from your utility bill, the units used and the degree days for the month. The program prints the cost per unit, the comfort energy cost (the cost of the energy used for heating or cooling, after taking off your usual non-heating use), the cost per degree day and an efficiency rating. Enter 1 to do another month.

Lines 250 and 260 subtract 500 units as an example of normal usage. The article asks you to replace that figure with your own average from months when you neither heat nor cool: electricity use in line 250 and fuel use in line 260.

The article says the program runs on a 1K ZX81, but in 1K it runs out of memory (report 4) before it prints the last two results. It runs in 2K.

Published in Syntax December 1982 ([Home Energy Analysis](https://timexsinclair.com/article/home-energy-analysis/)).

## Source Code

```
  10 LET L$=""
  20 CLS
  30 PRINT
  40 PRINT "***** HOME ENERGY ANALYSIS*****"
  50 PRINT
  60 IF L$="A" OR L$="H" THEN GOTO 100
  70 PRINT "CHOOSE ONE; A-AIR COND. H-HEAT"
  80 INPUT L$
  90 GOTO 20
 100 PRINT "MONTH? (ABBREVIATE) ";
 110 INPUT K$
 120 PRINT K$
 130 PRINT "COST? ";
 140 INPUT X
 150 PRINT X
 160 PRINT "UNITS USED? ";
 170 INPUT Y
 180 PRINT Y
 190 PRINT "DEGREES DAYS? ";
 200 INPUT Z
 210 PRINT Z
 220 PRINT
 230 LET A=X/Y
 240 PRINT "COST PER UNIT ";A
 250 IF L$="A" THEN LET Y=Y-500
 260 IF L$="H" THEN LET Y=Y-500
 270 LET D=A*Y
 280 PRINT K$;" COMFORT ENERGY COST ";D
 290 LET B=D/Z
 300 PRINT "COST PER DEGREE DAY ";B
 310 LET C=Y/Z
 320 PRINT "EFFICIENCY RATING ";C
 330 PRINT
 340 PRINT "ENTER 1 TO CONTINUE, 2 TO STOP"
 350 INPUT K
 360 IF K=1 THEN RUN
```