The following outlines example one-off or low volume cost price costing for the Heatpump Monitor.
Total £53.27 ex VAT including £28.93 ex VAT prototype one-off PCB from Ragworm (100mm x 80mm PCB standard pricing in one-off - £34.72 inc VAT). Total £63.92 including VAT (20%) + misc shipping costs to do one-off prototype/DIY.
See HeatpumpMonitor/BOM&Costing_1x.ods
A batch of 20x heatpump monitor boards start to give significant savings on the PCB cost and a couple of the other components, the cost price drops to £29.61 ex VAT in these quantities.
See HeatpumpMonitor/BOM&Costing_20x.ods
Some of the components in the heatpump monitor are shared with other OpenEnergyMonitor units. Because we order these in much larger quantities we are able to get a lower price on some items. This drops the cost price to near £26 ex VAT.
The cost price of the heatpump monitor would be less if the PCB was ordered in larger quantities. Ordering in 50x would reduce the cost price by about £3, ordering in several hundred would reduce the cost price by about £6.
Following the advice of other open hardware projects the sale price we typically charge is around 2.0-2.3x the cost price for OpenEnergyMonitor's main products. There's a good series of articles on pricing and other key considerations for maker businesses here: http://blog.ponoko.com/2010/11/16/ten-rules-for-maker-businesses-by-wireds-chris-anderson-%E2%80%94-rule-1
At a sale price of 2.0x cost price the heatpump monitor kit costs £26 x 2.0 = £52 ex VAT (£62.40 inc VAT).
All pricing below is ex VAT
| Component name | Quantity | Cost | Product | Supplier | Unit cost | Price Quantity | Minimum Order Quantity |
| Heatpump monitor PCB | 1 | £28.93 | Ragworm | 1 | 1 | ||
| Connectors and headers | |||||||
| 3.5mm CT jack sockets | 3 | £1.04 | 20-0157 | rapid | £0.346 | 1-24 | 1 |
| 2.1mm DC ACAC socket | 1 | £0.19 | 20-0970 | rapid | £0.190 | 10-99 | 10 |
| 3 Way 3.5mm terminal block | 9 | £1.71 | 21-3001 | rapid | £0.190 | 10-99 | 10 |
| USB mini | 1 | £0.75 | 565790511 | farnell | £0.745 | 1-24 | 1 |
| ESP-12 | 1 | £2.00 | ESP12 | Ebay | £2.000 | 1 | 1 |
| RFM69 | 1 | £3.20 | RFM69 | Ebay | £3.200 | 1 | 1 |
| 2 way headers | 3 | £0.06 | 1593411 | farnell | £0.020 | 100-499 | 100 |
| 6 way headers | 2 | £0.52 | 1593415 | farnell | £0.261 | 10-49 | 10 |
| 3 way header | 1 | £0.07 | 1593412 | farnell | £0.070 | 50-99 | 50 |
| jumper | 3 | £0.24 | 22-0690 | rapid | £0.080 | 10-99 | 10 |
| 5x2 way female header RASPI | 1 | £0.10 | 19-0284 | rapid | £0.100 | 10-99 | 10 |
| Capacitors | |||||||
| 100nf | 7 | £0.16 | 08-0235 | rapid | £0.022 | 10-99 | 10 |
| 22pf | 2 | £0.02 | 08-0046 | rapid | £0.012 | 10-99 | 10 |
| 10uf | 6 | £0.26 | 11-0825 | rapid | £0.044 | 1to9 | 1 |
| 1u | 1 | £0.06 | 11-0855 | rapid | £0.060 | 1to9 | 1 |
| 47u | 1 | £0.07 | 11-0835 | rapid | £0.068 | 1to9 | 1 |
| Resistors | |||||||
| 470k 5% | 8 | £0.05 | 62-0434 | rapid | £0.006 | 100 | pack of 100 |
| 10k 5% | 4 | £0.02 | 62-0394 | rapid | £0.006 | 100 | pack of 100 |
| or 10k 1% | 62-3474 | rapid | £0.012 | 100 | pack of 100 | ||
| 4.7k 5% | 1 | £0.01 | 62-0386 | rapid | £0.006 | 100 | pack of 100 |
| 100k | 1 | £0.01 | 62-0418 | rapid | £0.006 | 100 | pack of 100 |
| 100R 5% | 1 | £0.01 | 62-0346 | rapid | £0.006 | 100 | pack of 100 |
| CT burden resistors 22R or 100R | 3 | £0.04 | 62-3426 | rapid | £0.012 | 100 | pack of 100 |
| 120K | 1 | £0.01 | 62-3500 | rapid | £0.012 | 100 | pack of 100 |
| 5k6 | 1 | £0.01 | 62-0388 | rapid | £0.006 | 100 | pack of 100 |
| 56r | 1 | £0.01 | 62-0340 | rapid | £0.006 | 100 | pack of 100 |
| Other | |||||||
| 16 Mhz crystal | 1 | £0.21 | 90-2378 | rapid | £0.212 | 1to24 | 1 |
| 1N4148 or 1N4001? | 1 | £0.01 | 50-0381 | rapid | £0.014 | 50-99 | 50 |
| atmega328 | 1 | £2.41 | 1715487 | farnell | £2.410 | 1to9 | 1 |
| 28pin DIL | 1 | £0.45 | 2445626 | farnell | £0.453 | 10-99 | 10 |
| MCP1702 (3.3V) | 1 | £0.45 | 1331485 | farnell | £0.449 | 1to9 | 1 |
| LED | |||||||
| MBUS meter reader | |||||||
| BC307 or other PNP, BC557:1:C,2:B,3:E | 1 | £0.04 | 2453805 | farnell | £0.040 | 5-249 | 5 |
| BC337 or other NPN,BC547:1:C,2:B,3:E | 2 | £0.08 | 2453790 | farnell | £0.040 | 5-249 | 5 |
| 220k | 1 | £0.01 | 62-0426 | rapid | £0.006 | 100 | pack of 100 |
| 33k | 1 | £0.01 | rapid | £0.006 | 100 | pack of 100 | |
| 39k | 1 | £0.01 | 62-0408 | rapid | £0.006 | 100 | pack of 100 |
| 22k | 1 | £0.01 | 62-0402 | rapid | £0.006 | 100 | pack of 100 |
| 3k3 | 1 | £0.01 | 62-0382 | rapid | £0.006 | 100 | pack of 100 |
| 82r | 1 | £0.01 | 62-0344 | rapid | £0.006 | 100 | pack of 100 |
| 1K | 2 | £0.01 | 62-0370 | rapid | £0.006 | 100 | pack of 100 |
| 2 way header female | 4 | £0.14 | 19-0081 | rapid | £0.034 | 50-99 | pack of 50 |
| 2 way headers | 4 | £0.08 | 1593411 | farnell | £0.020 | 100-499 | 100 |
| 5v to 24v boost converter | 1 | £1.99 | ebay | £1.990 | 1 | 1 | |
| MBUS meter reader cost | £2.38 | ||||||
| Total Component cost | £16.52 | ||||||
| PCB cost | £28.93 | ||||||
| Enclosure | |||||||
| EmonTx v3 aluminium enclosure | 1 | £4.74 | EBS80 | Lincoln Binns | £4.740 | 1to9 | 1 |
| Laser cut facia pack | 1 | £3.00 | recycled acrylic | custom | £3.000 | 1 | 1 |
| Enclosure screws | 8 | £0.08 | 33-3415 | rapid | £0.010 | Pack of 100 | Pack of 100 |
| Total enclosure cost | £7.82 | ||||||
| Cost price (components, case and PCB) | £53.27 | ||||||
| Cost price no case | £45.45 |
Costing summaries for different options & volumes. All prices are for unassembled kits.
First figure: cost price, second figure sale price (cost price x 2.0). See above.
With case:
- 1x £53.22
- 20x £29.61, £59.22
- OEM £25.88, £51.76
Without case:
- 1x £45.41
- 20x £23.26, £46.52
- OEM £20.30, £40.6
Spreadsheets:
First figure: cost price, second figure sale price (cost price x 2.0). See above.
With case:
- 1x £46.12
- 20x £22.96, £45.92
- OEM £20.68 £41.36
Without case:
- 1x £38.31
- 20x £16.61, £33.22
- OEM £15.10, £30.20
Spreadsheets: